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[Display omitted] • Localized heating systems are a proper solution for providing thermal comfort. • Providing personalized heating by radiation or conduction is more convenient, so the inhaled air is kept cool and pleasant. • Local radiant heating systems directly heat the body without heating the environment, leading to lower energy consumption. • With local radiant heating systems, proper thermal comfort and sensation can be achieved even at low air temperatures. Localized heating systems are a proper solution for providing thermal comfort while lowering energy consumption in cold environments. Local radiant heating systems provide thermal comfort at lower air temperatures than convective systems which heats air, resulting in cool and pleasant inhalation air. This paper reviews experimental studies regarding local radiant heating systems considering thermal sensation and comfort. These systems can heat body directly, often with a big view factor toward the body. They do not necessarily heat the air and environment, leading to lower energy consumption. Other types of heating systems combined with local radiant heating systems are also reviewed in this paper. According to reviewed studies, localized methods improved thermal comfort, and the same thermal sensation could be achieved in lower air temperatures, especially when using local radiant heating systems. To design local radiant heating systems properly, improvement of existing local thermal comfort and sensation modeling based on radiant heat transfer is needed. [ABSTRACT FROM AUTHOR]

In times of great transition of the European construction sector to energy efficient and nearly zero energy buildings (nZEB), a market observation containing qualitative and quantitative indications should help to fill out some of the current gaps concerning the EU 2020 carbon targets. Next to the economic challenges, there are equally important factors that hinder renovating the existing residential building stock and adding newly constructed high performance buildings. Under these circumstances this paper summarises the findings of a cross-comparative study of the societal and technical barriers of nZEB implementation in 7 Southern European countries. The study analyses the present situation and provides an overview on future prospects for nZEB in Southern Europe. The result presents an overview of challenges and provides recommendations based on available empirical evidence to further lower those barriers in the European construction sector. The paper finds that the most Southern European countries are poorly prepared for nZEB implementation and especially to the challenge/opportunity of retrofitting existing buildings. Creating a common approach to further develop nZEB targets, concepts and definitions in synergy with the climatic, societal and technical state of progress in Southern Europe is essential. The paper provides recommendations for actions to shift the identified gaps into opportunities for future development of climate adaptive high performance buildings. [ABSTRACT FROM AUTHOR]

The construction industry in the European Union is turning increasingly in the direction of sustainable building. A particular important component of sustainable construction strategy is represented by the reduction of operational energy in buildings. One popular solution for the reduction of heat losses through the exterior envelope is the thermal insulation with polystyrene panels, frequently used in composite systems (ETICS – External Thermal Insulation Composite Systems). These solutions are efficient for operational energy savings, contributing in the same time to the reduction of environmental pollution and degradation due to the current energy production systems. Still, they present some reliability problems, being vulnerable to wind actions. The paper proposes an alternative solution for fixing the polystyrene panels by replacing the adhesive mortar with anchors and regular mortar to compensate the flatness. The paper presents experimental results for adhesive bonding strength of adhesive and regular mortar to various substrates. The results were embedded into numerical models for determining the response to wind actions both for the classical and proposed solution. The paper presents a comparative analysis of the mechanical and economic performance for the two fixing solutions. Finally are discussed the advantages and disadvantages of the mechanical fixing solution proposed and are identified the main areas of application. [ABSTRACT FROM AUTHOR]

• Experiment in three homes using mixed-methods and physical measurements. • Indoor air temperature fluctuations like those of EMPC of space heating. • Night setback-users found the heating control unacceptable. • Acceptance was motivated by economic or environmental benefits. Recent simulation-based studies have indicated that Economic Model Predictive Control (EMPC) of space heating systems can exploit the thermal mass in residential buildings for demand response (DR) purposes in district heating systems. However, there is a lack of studies on residents' perception and acceptance of the fluctuating indoor air temperature behaviour inherent in EMPC of space heating. This paper reports on a case study featuring the residents of three one-story houses located in Denmark. The houses were equipped with technology enabling remote actuation of radiator thermostats and collection of various indoor environmental data. Four different temperature boost interventions mimicking the typical behaviour of EMPC of radiators were executed while a mixed-methods triangulation design, employing questionnaires and semi-structured interviews, was used to collect subjective data. Data showed that residents accepted the behaviour but only after the benefits of the EMPC were explained. The acceptance was motivated by either the prospect of saving money, environmental benefits, or a combination of both. The results thereby indicate that explaining the benefits of EMPC is important if residents are to abandon their current preferences and practices in favour of an EMPC concept. The explanation should consider the diversity in current preferences, expectations, and level of technological pre-knowledge. In addition, the paper also reports on a range of findings related to technical aspects of realising EMPC in practice. [ABSTRACT FROM AUTHOR]

In buildings, occupant behaviour is recognised as a major contributing factor to energy demand and in particular to heating consumption. To achieve thermal comfort within the heating season, people report to use heat in very different ways; for example behaviours include switching on the heating system, putting on warm clothes, drawing curtains, changing rooms, making a hot drink and using a hot water bottle. While research has focused on subjective accounts using interviews, diaries and questionnaires, little is known about the frequency and probability of these behaviours. Using a mixed-method approach, this paper reports on the results of a field study in dwellings using wearable and environmental sensors. The analysis investigates the probability of these behavioural responses as a function of seven independent variables; (1) external and (2) internal monitored temperature, (3) probability of heating being on or off, (4) time of the week, (5) time of the day, (6) the three categories of the predictive thermal comfort model, and (7) the three categories of the adaptive thermal comfort model. Results show that participants were more likely to increase their clothing and activity level as internal temperature decreased, although there was no significant change in activity level throughout the course of a day. Methodologically, this paper demonstrates the effectiveness of different statistical tools in analysing occupants’ behaviours. Substantively, this paper emphasises the need for future research to gather objective data on what people do. [ABSTRACT FROM AUTHOR]

Climate change and its consequences are of great concern. Buildings can be affected by climate change in different ways, such as changes in energy needs and thermal comfort. However, the challenge is to quantify and assess the uncertainties involved in future climate data as well as the relevant adoption strategies. The aim of this paper is to demonstrate potential energy consumption changes in high performance building construction systems in a changing climate. In this paper, current and future weather data of three time slices of 2020, 2050 and 2080 were used to simulate the performance of a simple building in Manchester and London using DesignBuilder software which employs Energy Plus as its calculation engine. Five of the most commonly used and high performance construction systems were examined in terms of energy consumption in this model and results are given. In general, this paper provides a useful methodology for simplification in design decision-making for current and future UK housing. It is observed that future climate scenarios do not have major effects in qualitative comparisons of construction systems. [ABSTRACT FROM AUTHOR]

Heating in wind-chilled environments is a serious task. The catalytic combustion heater (CCH) provides more efficient and cleaner in combustion compared to conventional heaters with high pollutant emission and low energy utilization. In this paper, the heating ability of CCH on human body in a wind-chilled environment (apparent temperatures between −14.8 °C and 12.4 °C) was investigated by collecting skin temperature and subjective thermal evaluation data from 23 subjects. The impact of cold air on localized heating of body parts by CCH was clarified using decision trees and dimensionless correlation coefficients. A human-computer interaction regulation strategy was proposed to simultaneously satisfy the requirements of effective heating, low energy consumption, and low pollution. Finally, CCH and a commercial heater were compared in terms of heating effectiveness and energy consumption in a real outdoor environment. The results showed that CCH effectively solved the problem of excessive cold extremities, and the temperature difference between thoracoabdominal area and extremities was reduced by 57.5–87.9% to within 2 °C. In a strong convective environment, wind speed was the decisive factor (coefficient of 0.95), inducing 46% radiant heat loss. Inputting personnel subjective perception, dynamic environmental parameters, and pollutant thresholds to adjust the injected gas flow enabled intelligent control. In a real cold scenario, the CCH saved 65.9% of energy compared to a commercial heater when achieving the same heating effect. This study provides a reference for the application of catalytic combustion technology in cold outdoor heating and also provides an important theoretical basis for the construction of heating strategies for CCH. [Display omitted] • A new catalytic combustion heat source was proposed to offset the cold exposure. • Heating characteristics of the CCH were obtained in wind-chilled condition. • The impact of strong convection on CCH radiant heating was quantified. • A comfortable and sustainable optimal control strategy for CCH was proposed. [ABSTRACT FROM AUTHOR]

This paper investigates experimentally the cooling performance of a concept, where the radiant ceiling is suspended from the hollow-core concrete slab and by ventilation supply in the plenum and the perforations of the ceiling tiles, ventilation air is distributed without ducts and air terminals to the occupied zone. Literature has proven that this concept allows for more streamlined installation procedures and excellent performance in terms of thermal comfort and draught. The paper reports experimental results from a climate chamber, where the concept was tested under both steady-state and quasi-steady conditions. The steady-state conditions were chosen to map the cooling performance with different air change rates, and different ventilation and water supply temperatures. The results showed that for air change rates of 3 h−1 in the occupied zone and water supply temperature of 17 °C, the cooling output from the ceiling increased by 10 %. The concept was also tested under quasi-steady conditions in a 48 h cycle to quantify the thermal buffering effect of the exposed upper concrete slab when subjected to ventilation supply air. The effect amounted to 11–12 % increased cooling capacity at the end of the working day when the driving temperatures between air, water and thermal zones were at their maximum. [ABSTRACT FROM AUTHOR]

Green roofs have been proposed for energy saving purposes in many countries with different climatic conditions. However, their cooling and heating potential strongly depends on the climate and building characteristics. In particular, the increase of the thermal capacity of green roofs compared to traditional roofs, if not controlled with insulation, may lead to higher cooling and heating loads. This paper discusses the energy saving potential of green roofs adopting a variable insulation strategy. A system consisting of a plenum located between a green roof and the room underneath and a sensor-operated fan that couples (or decouples) the green roof mass with the indoor environment was developed. The fan is activated and stopped using temperature based rules; the plenum is ventilated only when the fan works, creating a variable insulation system. Four cells with an insulated traditional roof, a non-insulated green roof, an insulated green roof, and a green roof with the variable insulation system have been tested in a hot and dry climate with mild winters over several years. This paper compares and discusses different plenum control algorithms. Results are particularly promising because the variable insulating system proved to adjust the thermal capacity of the roof effectively. In summer, the non-insulated green roof and the green roof with variable insulation system achieved the lowest indoor temperature; in winter, the insulated traditional roof and the variable insulation green roof system achieved the highest indoor temperatures. Measurements are hence compared with simulations. Finally, the energy saving potential of the new green roof system is evaluated. [ABSTRACT FROM AUTHOR]

Abstract: The increase of peak and energy demand during the cooling season is becoming a crucial issue, as well as the intensification of the urban heat island effect. This trend is observed at several latitudes, including areas where overheating was unknown at building and urban levels. This phenomenon involves different issues: reduction of greenhouse gases, quality and comfort in outdoor and indoor environment, security of energy supply, public health. The building sector is directly involved in this change and adequate solutions can provide great benefit at energy and environmental levels. Roofs in particular are envelope components for which advanced solutions can provide significant energy savings in cooled buildings or improve indoor thermal conditions in not cooled buildings. Cool materials keep the roof cool under the sun by reflecting the incident solar radiation away from the building and radiating the heat away at night. Roofs covered with vegetation take benefits of the additional thermal insulation provided by the soil and of the evapo-transpiration to keep the roof cool under the sun. These two technologies are different in: structural requirements, initial and lifetime maintenance costs, impact on the overall energy performance of buildings. This paper presents a numerical comparative analysis between these solutions, taking into account the several parameters that affect the final energy performances. By means of dynamic simulations, the paper depicts how cool and green roofs can improve the energy performance of residential buildings in different localities at Mediterranean latitudes. [Copyright &y& Elsevier]

Abstract: The employment of Heating, Ventilation and Air-conditioner (HVAC) technology is viable option for the dynamic thermal comfort in the transitional spaces where connect the interior and exterior space. In this paper, the optimization to thermal environment parameters in the hot summer and warm winter zone is benefit to human comfort, health and energy saving is discussed. According to the dynamic comfort equations and the advantage of artificial immune algorithm in solving combinatorial optimization to engineering problems, the artificial immune algorithm has been applied to the optimization of thermal parameters for the HVAC design within a transitional space. Furthermore, it is pointed out that the proposed method in this paper might be employed in the control of the HVAC conditioning system. [Copyright &y& Elsevier]

Abstract: This paper presents a review of studies on natural convection heat transfer in the triangular enclosure namely, in attic-shaped space. Much research activity has been devoted to this topic over the last three decades with a view to providing thermal comfort to the occupants in attic-shaped buildings and to minimising the energy costs associated with heating and air-conditioning. Two basic thermal boundary conditions of attic are considered to represent hot and cold climates or day and night time. This paper also reports on a significant number of studies which have been performed recently on other topics related to the attic space, for example, attics subject to localized heating and attics filled with porous media. [Copyright &y& Elsevier]

Abstract: Work stations in industrial spaces are frequently arranged at a significant distance from each other. Local heating applying, among others, the gas-fired direct radiant heaters, is a viable alternative to the central heating. Radiant heaters provide heat comfort to workers and guarantee the maintenance of higher temperatures of the surrounding walls at a lower indoor temperature. The advantage of heating by gas-fired radiant heaters is the lower operational cost comparing to another systems. It uses less energy to obtain 2–3K lower indoor temperature than in case of heating by conventional systems. The radiant temperature at work stations should be high enough to eliminate thermal discomfort, which in particular, is a result of radiant temperature asymmetry that may be caused by excessive and asymmetric overheating of the human body by a radiant heater. This paper includes formulas, based on the results of the self-designed test, which are then used in the calculation of the radiant temperature and the radiant temperature asymmetry, depending on the radiant heater position and the indoor temperature. This paper presents also the most recognized interrelations between the radiant temperature and its asymmetry. The discussed parameters are particularly significant in the heating process using high-temperature radiant heaters. [Copyright &y& Elsevier]

A solid-desiccant system that utilizes low grade heat is potentially a viable add-on to conventional HVAC systems since it can help reduce power consumption significantly, for achieving indoor thermal comfort conditions. In contrast to desiccant wheels which carry out adiabatic dehumidification, isothermal dehumidification process that may be realized by a cross-flow heat exchanger is much more efficient. In this paper, a novel mathematical model is developed to simulate heat and mass exchange phenomena of a desiccant coated fin tube heat exchanger (DCFTHX). This model takes solid side mass transfer resistance as well as fin efficiency into consideration. The model is validated using experimental results in the literature. It is also compared against simplified models to establish its utility. A parametric study is then conducted to investigate the effects of geometrical parameters as well as mass flow rate of water and air velocity on dehumidification and adsorption heat removal performance of the DCFTHX as well as the performance of the augmented air-conditioning system under warm and humid ambient conditions. Under the range of parameters and conditions simulated, if low grade waste heat (50 °C hot water) is available for regeneration, integration of DCFTHX sub-system with a conventional air conditioning system can yield as high as 31% energy savings (even when the additional power consumed by pumps and blower fans is accounted for). [ABSTRACT FROM AUTHOR]

Maintaining thermal comfort in built environments is important for occupant health, well-being, and productivity, and also for efficient HVAC system operations. Most of the existing personal thermal comfort learning methods require occupants to provide feedback via a survey to label the monitored environmental or physiological conditions in order to train the prediction models. Accuracy of these models usually drops after the training process as personal thermal comfort is dynamic and changes over time due to climatic variations and/or acclimation. In this paper, we present a hidden Markov model (HMM) based learning method to capture personal thermal comfort using infrared thermography of the human face. We chose human face since its blood vessels has a higher density and it is not covered while performing regular activities in built environments. The learning algorithm has 3 hidden states (i.e., uncomfortably warm, comfortable, uncomfortably cool) and uses discretization for forming the observed states from the continuous infrared measurements. The approach can potentially be used for continuous monitoring of thermal comfort to capture the variations over time. We tested and validated the method in a four-day long experiment with 10 subjects and demonstrated an accuracy of 82.8% for predicting uncomfortable conditions. [ABSTRACT FROM AUTHOR]

This paper investigates air-conditioning (AC) usage patterns and adaptive comfort behaviors in a Chinese residential context. Field measurements were conducted in 43 homes in Tianjin from May 14 th to November 20 th in 2016. Indoor temperatures and AC on/off events were recorded. Occupants’ “right-here-right-now” thermal perception and adaptive behaviors were collected. 4,743 AC events and 1,697 online comfort questionnaires were collected. Average duration for AC cooling events in summer was 3.24 hrs per house and the average duration for AC heating events in winter was 0.96 hrs per house. Tianjin residents were less sensitive to indoor air temperature, compared to those in offices. The indoor temperatures corresponding to 80% thermal acceptability ranged from 21.0℃ to 27.3℃. We also derived statistical models to predict the likelihood of adaptive behaviors (i.e. turning on AC, turning on fans and opening windows or doors) with regard to outdoor air temperatures. [ABSTRACT FROM AUTHOR]

Thermal energy storage (TES) systems with phase change materials (PCMs) as a known energy storage technology have a high potential for increasing the energy efficiency of buildings. In fact, the use of PCMs with various approaches, either active or passive, in the building helps to maintain the temperature in the thermal comfort range for occupants through decreasing the temperature swings, and lower energy consumption by the load reduction/shifting. Due to the significance of this issue, many research works have been carried out on the application of PCMs in buildings. In this study, the experimental works in the fields of PCMs in buildings are taken into account. The papers are classified based on heating, cooling, and air-conditioning. Besides these, the applications of nano-PCMs in buildings are reviewed. According to what has been carried out up to now, the gaps are identified and analyzed for preparing useful suggestions for future works. The recommendations and suggestions are presented at the end of the chapters as well as the conclusion, and the literature is summarized in some tables. [ABSTRACT FROM AUTHOR]

• Indoor thermal environment and AC usage behavior was investigated for low-quality centrally heated dwellings. • 90% of AC trigger temperature is 15 ℃ for the living room and 14 ℃ for the bedroom. • The heating demand drivers of cool housing are identified by heteroskedasticity-robust Ordinary Least Square. • The study presents new knowledge for appropriate way to meet actual heating demand while reducing energy use. • Relationships between indoor temperature, heath and energy use are discussed. In northern China, district heating systems without terminal control typically serve thousands of end-users, thus inevitably some users suffer from insufficient warmth and others are overheated indoors due to hydraulic imbalances. This paper aimed to understand the indoor thermal conditions and the actual heating demand in low-quality centrally heated dwellings. The driving force of heating demand was analyzed based on a smartphone survey of 233 households in cold climates, and field measurements of winter indoor thermal environment and AC supplemental heating behavior were conducted in a sample of 13 cool dwellings. Logistic regression and heteroskedasticity-robust Ordinary Least Squares were adopted to assess AC usage patterns and driving forces of heating demand, respectively. New knowledge has been gathered regarding average temperatures of 17.4 ℃ and 16.8 °C in cool housing living rooms and bedrooms, respectively, outside the human thermal comfort zone. Simultaneously, intermittent and partial AC usage patterns induced by time and air temperature were observed in these cool end-users for the comfort. The average daily running time of AC devices was 2.0 h for the living room and 1.8 h for the bedroom. There were statistically significant base linking occupants' heating demands to education level, household income, tenure type, presence of children, thermal experience and heating system. However, it was not a significant factor for household size. In addition, a rebound effect of building energy efficiency improvements on the interior temperature was also noticed. The results of this study shed light on better and target-oriented residential internal temperature or heating system design for both thermal comfort requirements and energy-savings. [ABSTRACT FROM AUTHOR]

The aim of this paper is to study and compare the temperature profile and energy performance of traditional and Vegetative Roofs (VRs) during winter season in Lebanon, a country in the Middle East. Three roof mockups were installed on the rooftop of the Chemical Engineering Department at the University of Balamand: a Traditional Gravel Ballasted Roof (TGBR) and two Extensive Green Roofs (EGRs) with different substrate depth and composition. Each minute, the temperature of air, on TGBR surface, and at different depths of EGR was recorded. The daily cooling and heating demands were also calculated. Results confirmed that VRs protect the roof membrane from high temperature fluctuations and decrease air temperature by a factor of one and a half during sunny winter days ( T airmax = 32 ° C ). Findings of this study also showed that the total cooling demand of EGR decreased by 90% compared to TGBR. [ABSTRACT FROM AUTHOR]

The capability to dynamically plan, predict, and control indoor conditioning allows to adapt to individual preferences of inhabitants and enables demand side management. While former mainly improves thermal comfort of inhabitants so does latter unlock ecological and financial opportunities mostly for energy utilities. Commonly, dynamic indoor conditioning is based on piece-wise constant indoor temperature constraints. This paper's contribution is the presentation of additional constraints: in particular ones expressed relative to the nominal behavior of a hydronic heating system. This allows to simultaneously harness the relevant process variables in particular during the pre-loading and post-loading phases of a load reduction. The findings are based on data sets acquired on 10 inhabited, residential buildings in Stockholm over a whole year. One of the findings is that building models need to be adaptable if predictive control is applied in practice. This adaptability is assured by a novel concept, i.e. a so called model manager on which the control is relying for the selection of the most accurate model. Centralized optimal control of buildings connected to a district heating network is challenging in practice due to a high computational load. In order to reduce it, the herein presented method elaborates plans only every hour instead of at every control step for optimal control. Since these plans cannot be optimal due to the lack of regular update a hitherto unknown cascaded control logic has been developed that corrects planning errors and other disturbances. Capabilities are demonstrated and compared to conventional controllers in dynamic simulations of a multi-zoned building. The herein presented method is to our knowledge the first to provide all flexibility desired by energy utilities and inhabitants alike through harnessing the consequences of transitions. [ABSTRACT FROM AUTHOR]

In electric buses, the heating, ventilation and air conditioning (HVAC) system is responsible for up to 50% of the energy consumption, thereby significantly affecting the efficiency. It is therefore necessary to identify improved thermal settings for the bus cabin to minimize the energy consumption, while guaranteeing good thermal comfort. To achieve this goal, this paper presents the results of climatic measurements in an electric bus in Berlin, Germany. These measurements were performed for outer temperatures between 5.3 °C and 7.8 °C and four cabin temperature settings. During the measurements, several climatic parameters and the energy consumption were measured, whereas the thermal comfort (TC) was evaluated via 71 passengers' surveys. The results show that the climatic conditions in the bus vary greatly depending on the position (up to 3 K difference in mean air temperature) and height (up to 8 K/m temperature-to-height ratio). Additionally, the surveys show that the mean value of the thermal comfort parameter TC is minimized to a value of 0.15 (corresponding to "comfortable" thermal perception) for a set temperature of 21 °C, whereas the thermal conditions are perceived as acceptable even with heating off. [ABSTRACT FROM AUTHOR]

There is a growing trend for the use of thermo-active building systems (TABS) for the heating and cooling of buildings, because these systems are known to be very economical and efficient. However, their control is complicated due to the large thermal inertia, and their parameterization is time-consuming. With conventional TABS-control strategies, the required thermal comfort in buildings can often not be maintained, particularly if the internal heat sources are suddenly changed. This paper shows measurement results and evaluations of the operation of a novel adaptive and predictive calculation method, based on a multiple linear regression (AMLR) for the control of TABS. The measurement results are compared with the standard TABS strategy. The results show that the electrical pump energy could be reduced by more than 86%. Including the weather adjustment, it could be demonstrated that thermal energy savings of over 41% could be reached. In addition, the thermal comfort could be improved due to the possibility to specify mean room set-point temperatures. With the AMLR, comfort category I of the comfort norms ISO 7730 and DIN EN 15251 are observed in about 95% of occasions. With the standard TABS strategy, only about 24% are within category I. [ABSTRACT FROM AUTHOR]

To date, religious facilities have received little attention in the published literature regarding energy use and efficiency. With unique operating and building characteristics, these buildings have distinct opportunities for analysis in regards to building energy use and occupant comfort. With overall lower average energy intensity, religious facilities rarely receive energy assessments or are operated by experienced personnel. Therefore, identifying common issues is critical for training church owners in energy efficiency. This paper presents an in-depth analysis of heating, ventilation and air conditioning (HVAC) systems and occupant comfort in two religious facilities. The analysis reveals that the largest opportunities for reduction in energy use come from proper maintenance and operation of HVAC equipment and schedules. Temperature setbacks are shown to be an important operational setting to reduce energy usage. An accompanying analysis on thermal comfort reveals that temperature setbacks must be coupled with sufficient preconditioning of the space to ensure occupant comfort during intermittent building occupancy. An analysis of CO 2 levels in the building during occupancy reveals the need for sufficient outside air to meet ventilation standards. [ABSTRACT FROM AUTHOR]

Current indoor thermal environment is usually automatically controlled based on a temperature set-point given by room occupants or building managers. However, investigation shows that many temperature set-points are far from the comfortable temperature range recommended by design handbooks. Such unreasonable temperature set-points will result in not only uncomfortable indoor thermal environment, but also waste of cooling or heating energy. The authors have proposed a methodology of satisfaction based control to take place of the traditional set-point based control. This paper describes the experimental comparison results between satisfaction based indoor thermal environment control and set-point based control. Two test-beds were set up and a series of experiments was conducted to compare control performances, user acceptances, user work performances and system energy consumptions of the set-point based and satisfaction based control. The comparison results show that the satisfaction based control can achieve more stable thermal environment. Both of the two control methods can get relatively high scores regarding user acceptance and work performance. There are no statistically significant differences for user acceptance and work performance between two control methods. However, satisfaction based control consumed 15.3% and 11.9% less energy at two test-beds respectively than set-point based control due to more reasonable temperature settings given by the satisfaction based control. [ABSTRACT FROM AUTHOR]

Model predictive control (MPC) has been studied in the building science realm for about three decades. However, the following two aspects of the building control have not been studied thoroughly in MPC research. One is the impact of the mixed-mode cooling system on the active heating ventilation and air conditioning (HVAC) energy consumption, and the other is the differences of individual thermal comfort preference and its impact on energy. This paper proposes an occupant-oriented mixed-mode EnergyPlus predictive control system to optimize HVAC energy consumption while meeting the individual thermal comfort preference. A web-based dashboard is implemented in the test-bed building for three months to collect individual thermal comfort preference data. The data analysis results suggest that occupants have various tolerances and preferences about thermal comfort. The simulation results show that, during one week of a typical swing season, the mixed-mode system further reduces the active HVAC energy consumption, and the diversified occupant thermal comfort preference has significant impact on HVAC energy consumption. [ABSTRACT FROM AUTHOR]

This paper assess the feasibility of using heating-cooling radiant panel in residential buildings in five different climate zones in Iran. This study leverages simulation modeling to evaluate the thermal performance of heating-cooling radiant panels. By defining new indices, applicability limiting factors of the radiant panels, i.e. condensation risk in cooling, and asymmetric radiation discomfort in heating are evaluated and compared in different climatic conditions. The system capacity and setpoints are calculated based on thermal comfort conditions, using PMV index in heating (PMV= -0.5) and cooling (PMV= +0.5) modes. Results of this study indicate that for dryer regions with less risk of condensation the radiant system can help home owners to save around 11.3% on their heating energy and 9.1% on cooling energy use. [ABSTRACT FROM AUTHOR]

Currently, heating and cooling systems used for achieving thermal comfort in commercial buildings represent a significant energy consumption. Traditionally, power supply installations of these Heating, Ventilation and Air Conditioning Systems (HVAC) present low efficiency. In these installations the power is supplied from the substation to the HVAC system by low voltage cables. Due to the long distances of the power distribution, the system suffers considerable energy losses. This paper proposes a decentralized power supply installation based on a power distribution at medium voltage, which achieves not only significant energy savings, but also important savings in material and person-hours. These improvements entail substantial savings in cost and CO 2 emissions. [ABSTRACT FROM AUTHOR]

In buildings, HVAC systems consume a high amount of energy to provide thermal comfort for occupants. A methodology is presented in this paper to control thermostat operation of the buildings considering the effects of indoor and outdoor boundary conditions and phase change material (PCM) characteristics. EnergyPlus v8.1 building energy simulation software was used to analyze the energy performance of the PCM incorporated building models and to implement Fanger model to control HVAC thermostat operation according to BS EN 15251:2007 thermal comfort categories. Three types of building HVAC schedule, PCM with different melting points and layer thicknesses were studied for Madrid climate zone. Moreover, the impact of occupants clothing on the energy consumption was investigated. Furthermore, payback analysis was conducted to find out the economic benefits of PCM integration into the building envelopes. Application of PCM improved the cooling and heating energy performances except for the office model in winter (heating period). Additionally, higher energy savings and lower payback periods were observed when PCM with higher melting point was applied to the buildings. Eventually, energy savings in PCM incorporated models were found to improve further when occupants changed their clothing behavior in winter. [ABSTRACT FROM AUTHOR]

This paper presents a cooperative fuzzy model predictive control (CFMPC) for heating and cooling of buildings. Because of different supply zones, the large time constants and the non-linear building dynamics with respect to the different seasons, a CFMPC concept is proposed. The overall non-linear building is split into different zones, which are consisting of input-coupled Takagi-Sugeno (TS)-fuzzy models. Each such TS-fuzzy model is constituted by a local linear model network (LLMN). The LLMN consists of local linear models (LLM), which are representing the different seasons: winter, transition season (fall and spring), and summer. The control of each LLM is realized by model predictive control (MPC). For each building zone the associated MPCs are output-blended by the fuzzy membership functions, which leads to fuzzy model predictive control (FMPC). In addition to the FMPCs a global MPC is controlling the thermally activated building systems, which affect all other zones. To coordinate the different controllers a cooperative iteration-loop is assumed, which leads to cooperative fuzzy model predictive control (CFMPC). The concept is developed for a specific demonstration building and can be easily adapted for other complex buildings. A simulation example demonstrates that the proposed CFMPC achieves a performance increase with less energy consumption, as compared to FMPC controllers and historical measured data of the demonstration building. [ABSTRACT FROM AUTHOR]

Phase Change Materials (PCM) technology can be used for thermal storage and peak load shaving. This paper presents the optimization study of a PCM-Air heat exchanger as well as the development of load shifting solutions which take into account the thermal comfort of the occupants and the indoor air quality. The exchanger contains macroencapsumated PCM (paraffin) and is conceived in a way that facilitates its integration in a ventilation system. It is aimed to shift space heating electrical consumption from peak to off-peak period. The study is performed using an experimentally validated numerical model based on the heat balance approach and the apparent heat capacity method. Several parameters were investigated during the optimization processes, including heat exchanger dimensions, PCM quantity and properties, seeking the configuration with the optimal compromise between stored heat and the time needed for the charging/discharging process. The numerical model was coupled to a building simulation model with several control strategies investigating different scenarios over a one- month winter period. The scenarios vary with increasing complexity, first considering load shifting and thermal comfort, then adding the final price of electricity consumption and finally taking into account the indoor air quality. [ABSTRACT FROM AUTHOR]

Passive Houses are buildings which provide comfortable indoor conditions at an extremely low heating and cooling load. The peak daily average heating and cooling loads are typically below 10 W/m 2 and annual useful energy demands are below 15 kW h/(m 2 a). The Passive House standard was originally developed in Germany. In this paper we show by hygro-thermal dynamic simulation that it is possible to realize residential Passive Houses in all of the world's relevant climate zones, represented here by Yekaterinburg, Tokyo, Shanghai, Las Vegas, Abu Dhabi, and Singapore. The window quality, insulation levels, and mechanical services all depend on the climate as well as on the building's shape and orientation. The resulting annual energy demand for space conditioning of the Passive Houses is 75 to 95% lower than that of a traditionally insulated building of the same geometry. In humid climates like Shanghai or Singapore, special attention must be paid to humidity aspects. In climates which are hot and humid all year long, the total useful energy demand for sensible and latent cooling may exceed 70 kW h/(m 2 a) even in a Passive House. Finally, it is shown that the architectural quality is not compromised by the Passive House requirements. [ABSTRACT FROM AUTHOR]

Conventional weather-compensated heating controllers are often configured to deliver more heating than necessary, resulting in energy losses. Furthermore, they cannot take into account future climate conditions, and yield less than optimal thermal comfort. We have developed a non-invasive add-on module for existing heating controllers that implements an adaptive, model-predictive heating control algorithm. This algorithm helps the heating controller deliver a heating energy just sufficient for maintaining thermal comfort, resulting in energy savings. In this paper we report on the energy savings measured on ten buildings equipped with this device. By monitoring the space heating energy during the 2013–2014 heating season, and by periodically alternating between the new controller and the reference controller, we establish the energy signature of all buildings with both controllers. The comparison of the energy signatures yields the relative energy savings achievable with the new controller. These energy savings are positive for all test sites, with a mean of 28 ± 4% (standard error of the mean). [ABSTRACT FROM AUTHOR]

Energy performance simulation is a generally used method for assessing the energy consumption of buildings. Simulation tools, though, have shortcomings due to false assumptions made during the design phase of buildings, limited information on the building's envelope and installations and misunderstandings over the role of the occupant's behaviour. This paper presents the results of a Monte Carlo sensitivity analysis on the factors (relating to both the building and occupant behaviour) that affect the annual heating energy consumption and the PMV comfort index. The PMV results are presented only for the winter (heating) period which is important for energy consumption in Northern Europe. The reference building (TU Delft Concept House) was simulated as both a Class-A and a Class F dwelling and with three different heating systems. If behavioural parameters are not taken into account, the most critical parameters affecting heating consumption are the window U value, window g value and wall conductivity. When the uncertainty of the building-related parameters increases, the impact of the wall conductivity on heating consumption increases considerably. The most important finding was that when behavioural parameters like thermostat use and ventilation flow rate are added to the analysis, they dwarf the importance of the building parameters. For the PMV comfort index the most influential parameters were found to be metabolic activity and clothing, while the thermostat had a secondary impact. [ABSTRACT FROM AUTHOR]

Climate change has been shown to significantly alter the heating and cooling needed to maintain thermal comfort within a home. However, limited studies have investigated the impact on the design philosophy associated with achieving an energy efficient building envelope with the onset of climate change. Applying robust future TMY for 2070 the change in heating and cooling demand has been studied in this paper for various combinations of external and internal wall insulation, roof insulation, reflective foil, thermally reflective roofs and different floor coverings. A building thermal model was used for the mild temperate climate of Adelaide, Australia, which requires both heating and cooling, but is dominated by heating. Climate change was found to increase and shift this demand to cooling dominated. It was determined that with climate change, heating becomes significantly less important in better insulated buildings and therefore measures which reduce cooling load are more critical. It is concluded that in this climate zone, climate change design approaches need to dramatically change to focus on cooling, contrary to present strategies. [ABSTRACT FROM AUTHOR]

The Chinese Kang, a traditional heating device, is widely used in northern rural China. It recovers the heat from cooking smoke and provides local thermal comfort to people sitting or lying on it. However the heat supply ability of the traditional Kang is limited due to constraints of the surface temperatures and heat transfer coefficients. In this paper, a new Chinese Kang with forced convection (CKFC), which adopted hot water as the heat transfer medium and added a small fan to enhance convective heat transfer, was developed. A full-scale CKFC system was constructed for actual application in a rural house and its thermal performance was measured. Experimental data show that during the space heating period, the heating power of forced air convection ranged from 625 W to 1170 W, while that through the CKFC surfaces was only 200–500 W in the local heating or space heating mode to maintain local thermal comfort. Meanwhile, the CKFC retained the merits of a traditional Kang by providing local thermal comfort. The measured asymmetry of Kang plate surface temperatures was 6.7 °C. Overall, the CKFC has satisfactory performances as a new heating terminal device in rural houses. [ABSTRACT FROM AUTHOR]

Several studies have shown that the actual energy performance of buildings can differ significantly from its designed value. An important part of this performance is constituted by the building fabric's thermal performance. A common method to evaluate the latter for an actual building is the co-heating test. The co-heating test comprises a quasi-stationary heating experiment followed by linear regression analysis of aggregated building performance data. This paper reviews related research work and cristallises the current state-of-the-art. The physical phenomena working behind the scenes of the generally assumed simplified heat balance are discussed. Statistical constraints generally prevent these from being uncovered fully during the analysis. Multiple linear regression is proposed as the most sensible method to analyse co-heating measurement data. A novel way to visualise such analysis, deduce building performance data graphically and compare different co-heating test results is presented. [ABSTRACT FROM AUTHOR]

This paper proposes a new method for an optimal control of the heating system at the building scale. This control is a new approach of energy planning that aims to decrease the heating consumption/expenses over a defined prediction horizon while respecting the occupants’ thermal comfort. It employs a simplified building thermal model to simulate the building thermal behavior taking into consideration the weather predictions. This approach is based on the application of Monte Carlo method, i.e., a random generator for the heating system scenarios. The aim is to determine the optimal heating plan for the prediction horizon that fulfills the constraints regarding the thermal comfort of occupants and the minimization of the energy consumption/expenses together with achieving a load shedding. [ABSTRACT FROM AUTHOR]

Abstract: HVAC energy savings have been a key focus of recent building energy management efforts, but the savings typically reduce thermal comfort for building occupants. Established thermal comfort models use complex and person-specific parameters, such as clothing insulation and metabolic rate, to predict individual comfort levels, making the design of automated comfort modelling systems a highly challenging endeavour. In this paper, we investigate the use of humidex, which encapsulates both temperature and humidity, as an easily measurable and highly representative indoor thermal comfort predictor. We verify the feasibility of humidex as an indoor thermal comfort predictor by contrasting its performance to that of the best feature set (the feature set that best predicts the thermal comfort) constructed jointly by recursive sequential forward selection and support vector regression. The analysis using the global datasets, including data from seven climate zones across three continents, shows that humidex is a favourable and easily measurable indoor thermal comfort descriptor when humidity is significant. We take away the message from the analysis and design, develop, and deploy a system that couples a deployment of sensor nodes in an office environment, where each node collects the ambient temperature and humidity at each person's desk, and an automated survey mechanism to record people's thermal sensation votes. We use subjective response through the surveys as ground truth to validate the performance of the thermal comfort prediction using humidex. The results confirm our analysis of global datasets and show that humidex is a good predictor of indoor thermal comfort at high humidity. [Copyright &y& Elsevier]

Abstract: Since Willis Carrier’s invention of air conditioning in 1911, we traditionally think about building conditioning in terms of the heating and cooling of a building’s indoor air. A better idea is the heating and cooling of a building’s mass. The latter has been called the radiant method, of which a most attractive strain is the thermally activated building systems (TABS) proposed by Robert Meierhans in 1990s. In this paper, a resistor–capacitor (RC) model is built in Matlab/Simulink for studying the system requirement of a TABS-equipped building-room. Specifically, what is the requirement in the envelope thermal resistance and activated TABS thermal mass of the room so that it is able to keep the room’s indoor operative temperature within the comfort range with its surroundings at neutral mean ambient temperature? Systematic simulations show that at neutral ambient temperature, the room’s manageability requires the correct selection of thermal mass at normal value and thermal resistance within minimum envelope resistance range (MERR). With its surroundings at above neutral ambient temperature, the room with the required mass-envelope combination functions robustly, albeit with a slightly larger operative temperature variation. We introduce the term thermally manageable building, defined as buildings that can be managed with off-peak equipment, either mechanical equipment (e.g., a chiller) or (natural energy gradient driven) low-power equipment (e.g., a cooling tower). Simulation results also show that while the mean operative temperature level is maintained by cooling equipment (mechanical or low-power one), the operative temperature variation is primarily a function of a building’s thermal mass and a building’s envelope thermal resistance and, only to a small extent, a weak function of mean ambient temperature and the diurnal temperature amplitude. [Copyright &y& Elsevier]

Abstract: Rooflights have become the common installations for industrial buildings to meet both the human health requirements for natural light and the need to save artificial lighting energy, especially for retail or distribution sheds that have big roof to floor area ratios and limitations of using glazing on side elevations. Since almost all of these buildings normally operate during daytime, an opportunity exists to save lighting energy by fitting automatic artificial lighting control. However, due to solar gains through the rooflights, the buildings are vulnerable to summer overheating. If overheating occurs regularly or over sustained periods, it will lead to the need for mechanical cooling, which inevitably results in more operational energy consumption in addition to the initial installation cost. To remedy this potential problem, natural ventilation through ridge openings is explored in this paper because it consumes almost no extra operational energy. Thermal modelling is therefore implemented with focus on influences of lighting control on energy consumption and effects of natural ventilation on reducing overheating. The modelling results indicate that lighting control can save lighting energy by 70% and the use of both ridge ventilation and lighting control can reduce overheating hours considerably, as internal heat is dissipated through the ridge openings and lighting heat gains are cut. In addition, converted from lighting and heating energy used, the overall CO2 reduction can reach 45% when both lighting control and ridge ventilation are applied. The findings from the study would encourage the use of rooflights for industrial buildings and would provide guidance on how to save operational energy while ensuring the thermal comfort inside the buildings. [Copyright &y& Elsevier]

Abstract: This paper described the development of regression models which are able to predict office building annual heating, cooling and auxiliary energy requirements for different HVAC systems as a function of office building heating and cooling demands. In order to represent the office building stock, a large number of building parameters were explored such as built forms, fabrics, glazing levels and orientation. Selected parameters were combined into a large set of office building models (3840 in total). As different HVAC systems have different energy requirements when responding to same building demands, each of the 3840 models were further coupled with five HVAC systems: VAV, CAV, fan-coil system with dedicated air (FC), and two chilled ceiling systems with dedicated air, radiator heating and either embedded pipes (EMB) or exposed aluminium panels (ALU). In total 23,040 possible scenarios were created and simulated using EnergyPlus software. The annual heating and cooling demands and their HVAC system''s heating, cooling and auxiliary energy requirements were normalised per floor area and fitted to two groups of statistical models. Outputs from the regression analysis were evaluated by inspecting models best fit parameter values and goodness of fit. Based on the described analysis, the specific regression models were recommended. [Copyright &y& Elsevier]

Abstract: The occupants’ behaviour has a great influence on the energy demand, management and consumption of a building. This paper investigates the influence of three parameters related to human behaviour through their modes of occupations (based on family size, management of the heating system and management of the heated area) on the housing heating loads of a standard dwelling in Belgium. Seven levels of insulation were tested: no insulation, two intermediate levels corresponding to 3 and 6cm of insulation, the current standard for new buildings in Belgium, the low energy standard, the very low energy standard and the passive house standard. Multi-zone simulations were performed with a dynamic thermal simulation software. The impact of occupants’ lifestyle and the interactions between occupation modes and insulation levels are highlighted. These results prove that the more the building is insulated, the more the lifestyle proportionally influences the heating loads. One important strategy for reducing heating consumption during the whole life cycle of the building is adapting the size of the house and its occupation modes to the evolution of family size. However, insulation is paramount, and increasing the insulation of the house provides generally better results than merely adapting the occupation mode. [Copyright &y& Elsevier]

Abstract: Our paper proposes to present the static heat balance of the human body and the sensitivity range of the comfort equation through average skin temperature and heat loss by sweating, based on Fanger''s work. We will investigate which measurement methods he used to develop the two heat balance equations. In addition a comfort diagram will be used to illustrate its sensitivity at various thermal load levels. [Copyright &y& Elsevier]

Abstract: Thermal mass can be effectively used for controlling temperature in buildings. Based on its location and function, building thermal mass can be classified as interior thermal mass and exterior (envelope) thermal mass. In this paper, the dynamic heat transfer performance of exterior Planar Thermal Mass (ePTM) subject to sinusoidal heating and cooling is investigated. When the mean value of outdoor air temperature is equal to indoor air temperature, solutions of temperature distribution and heat flux in ePTM are deduced analytically. Using the analytical solutions, heat exchange and thermal storage of ePTM are attained. Correspondingly, the time lag and the decrement factor are obtained; they show similarity characteristics—independent of environment temperatures. When the two temperatures are not equal, an approximated temperature distribution solution is developed based on the principle of superposition, which has been validated by numerical solutions. The approximated solution is then used to investigate the heat exchange between the ePTM and the environment. In contrast to the common belief that a large thermal mass has an apparent insulating effect, no “insulating effect of mass” under sinusoidal heating and cooling is found in this investigation. Another two rules of thumb based on common belief are corrected: a wood wall is better than a concrete wall of same thickness as exterior walls in terms of the time-lag effect and the decrement factor. The effect of the time lag is not the longer the time lag is the better its contribution to thermal comfort becomes. [Copyright &y& Elsevier]

Abstract: It is important to develop solar energy resource potential for improving indoor thermal comfort. In this paper, we used the statistical method to analyze observation data for temperature change in an elementary school classroom located in the clod region. The temperature data are recorded hourly in outdoor, the sunspace attached (SA), the classroom with a SA, and the reference classroom (RC) respectively. Results show that the daily mean temperature of the classroom with a sunspace attached (CAS) is higher 6.6°C than RC in the heating period. The heating effect of the sunspace is obvious during the day, while a lot of heat loses at night. To reach the indoor suitable temperature of 16°C, the fuel 315.51kgce are required, and only 61.1% of the heating requirement of the classroom are met. In order to increase the heat effect of SA, it is essential to improve the structure of the sunspace and building material properties. [Copyright &y& Elsevier]

Abstract: This paper identifies the impact of thermostat strategies on heating and cooling energy consumptions in buildings, thus suggesting the importance of a database for understanding the effect of thermostat settings and for deciding energy-conscious strategies. Using computer simulation, diverse thermostat strategies – change of setback period, change of set-point temperature, and change of setback temperature – were tested parametrically in a typical USA single-family homes, located in two climate zones, namely cold (Detroit, Michigan) and hot-humid (Miami, Florida). Analysis revealed that heating and cooling systems were significant energy-consuming components in each climate zone. Accordingly, heating energy in cold climate zones and cooling energy in hot-humid climate zones have potential for matchingly significant saving. Diverse thermostat strategies (changes of setback period, of set-point, of setback temperature) demonstrated their obvious impacts on such saving. In the cold climate in particular, the heating system showed the most significant energy-saving effect via proper thermostat strategies. Proper setback period, set-point and setback temperature need to be established to achieve energy efficiency in residential buildings. [ABSTRACT FROM AUTHOR]

Abstract: A traditional Chinese heating system, the Chinese Kang, is used by 175 million people in detached houses in the rural regions of China, especially in Northeast China. This system utilizes biomass such as corn stalks, straw, corncob and energy plants as the heat sources. The objective of this paper is to establish a set of models to simulate the energy performance of the Kang heating system in one Chinese detached house. An experimental field study was carried out to collect practical parameters in a newly constructed Chinese detached house. The dynamic performance of the Kang heating system was simulated by using IDA-ICE 4.0 embedded with an empirical model built in the field study. The results show that the simulation can obtain good overall agreement with the field measurement results. It was confirmed that the Kang model created by IDA-ICE 4.0 is capable of simulating the performance of the Kang system and of calculating energy consumption in the detached house. Moreover, the result reveals that the thermal environment in the present Chinese detached house is still poor during the severe cold season if only the Kang system is used to heat the whole house. [ABSTRACT FROM AUTHOR]

Abstract: In heating mode, fresh air is still essential for a chilled panel system in order to ensure the indoor air quality. In this paper, a chilled ceiling panel system was designed and built in a typical office room. The thermal environment and thermal comfort in the room were fully measured and evaluated by using the Fanger''s PMV–PPD model and the standard of ISO 7730 respectively, when room was heated in two modes, one of which is the chilled panel heating mode and the other of which is the combined heating mode of chilled panel and supply air. The research results indicate that in the combined mode, ceiling ventilation improves the general thermal comfort and reduces the risk of local discomfort. Under the condition of same general thermal comfort, the heating supply upper limit of chilled panel can be increased by 12.3% because of air mixing effect caused by introduction of air ventilation. [Copyright &y& Elsevier]

Abstract: This paper presents a predictive control structure for thermal regulation in buildings. The proposed method exploits the intermittently operating mode of almost all types of buildings. Usually the occupation profile can be known in advance and this fact will be used to reduce the energy consumption without decreasing the thermal comfort during the occupation. For that purpose, the predictive control strategy is first presented for a single zone building then extended to a multizone building example. Two opposite control strategies commonly exists: the decentralized control structure, which does not offer good performances especially when the thermal coupling among adjacent rooms is not negligible, and on the other hand, the centralized control for which the computational demand grows exponentially with the size of the system, being very expensive for large scale buildings. Our solution is based on a distributed approach which takes the advantages of both methods mentioned above. A distributed MPC algorithm with one information exchange per time step is proposed with good control performances and low computational requirements. Simulations and a comparison performance table end the article. [Copyright &y& Elsevier]

Abstract: This paper presents a detailed meta-analysis of end and primary energy use for heating, cooling and ventilation of 11 low-energy non-residential buildings and one residential building in Germany that belong to the EnOB research program launched by the German Federal Ministry for Economy. In particular, the analysis emphasizes the substantial impact of auxiliary energy use on the efficiency of heating and cooling performance. The investigated buildings employ environmental energy sources and sinks – such as the ground, ground water, rainwater and the ambient air – in combination with thermo-active building systems. These concepts are promising approaches for slashing the primary energy use of buildings without violating occupant thermal comfort. A limited primary energy use of about 100kWhprim/(m2 neta) as a target for the complete building service technology (HVAC and lighting) was postulated for all buildings presented. With respect to this premise, a comprehensive long-term monitoring in high time resolution was carried out over the course of two to five years, with an accompanying commissioning of the building performance. Measurements include the energy use for heating, cooling, and ventilation, as well as the auxiliary equipment, the performance of the environmental heat source and sink, and local climatic site conditions. [Copyright &y& Elsevier]