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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]

• 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]

The development of the combined radiant floor and fan coil heating (RF-FCH) systems have improved the energy efficiency. In this study, the heating capacity and system operation state of the combined heating system were analyzed by experiments. The heating influencing factors of the combined heating system were investigated by two-way analysis of variance (ANOVA) and the Pearson correlation coefficient. Based on the technique for order preference by similarity to ideal solution (TOPSIS) the optimal operation scheme was determined. The results show that during the operation of the combined heating system, the fan coil bears significant heating capacity. The fan coil heating capacity accounts for about 62.2%-70.4% of the total heating capacity. The radiant floor plays an increasingly important role in the combined heating system with the decreasing outdoor temperature. The radiant floor response time varies from 1.5 h to 5.4 h. The fan coil responds faster to outdoor temperature changes compared to the radiant floor. The control of the fan coil can be considered as the dominant factor for dealing with outdoor temperature changes. The operation status of the RF-FCH system is mainly affected by the outdoor temperature. The energy conversion efficiency of the RF-FCH system increases with the increase of outdoor temperature. The energy efficiency ratio (EER) of the RF-FCH system varies from 2.2 to 3.2. The Pearson correlation coefficient analysis results are consistent with two-way ANOVA. Compared with the radiant floor, the indoor temperature and system energy consumption were more influenced by fan coil supply water temperature. When the evaluation indexes of the TOPSIS method have the same weight, the scheme with the fan coil supply water temperature of 32 °C exhibits a better performance. The innovation of this paper is that the best water supply scheme of the combined system is determined by TOPSIS method, which provides guidance for engineering projects. [ABSTRACT FROM AUTHOR]

• Simplified models for heat transfer and surface temperature were established. • Calculated heat transfer and surface temperature agreed well with experimental data. • Heat transfer and surface temperature linearly changed with mean water temperature. • The pipe space clearly affected the heat transfer and surface temperature. • Heat transfer and surface temperature varied greatly as the transition changed. Prefabricated radiant heating and cooling (RHC) system is a typical form of high efficiency and lightweight radiant terminal, which has been extensively used in the residential and non-residential buildings. Heat transfer and surface temperature are the key parameters for rational design of a prefabricated RHC system. Therefore, in this paper, based on the analysis of the heat transfer mechanism, simplified models and numerical models were established for calculating the heat transfer and surface temperature of the prefabricated floor or ceiling RHC system. Compared with experimental test results, when the supply water temperature increased from 35 °C to 50 °C under heating condition or from 13 °C to 19 °C under cooling condition, the relative errors calculated by the simplified models were between −10.8% and 3.7% and between −3.8% and 5.0% for the heat transfer and surface temperature of the prefabricated floor RHC system, and ranged from 0.8% to 6.9% and from −0.7% to 0.3% for the prefabricated ceiling RHC system. Moreover, the calculated heat transfer and surface temperature of the prefabricated ceiling or floor RHC system using the simplified models were highly consistent with the numerical simulation results. Hence, the calculation accuracy of the proposed simplified models for the heat transfer and surface temperature can meet the requirements of engineering application, which will provide the support for the rational design of a prefabricated floor or ceiling RHC system. [ABSTRACT FROM AUTHOR]

Due to the inherent complexity of multi-dimensional solutions for transient conduction in a multilayered building element, most heat balance-based algorithms assume that conduction occurs only in one dimension—through the building element between the inside and outside environments. Usually, since the length and width of the elements are much greater than the thickness of the element, this is a valid assumption. However, there are some cases such as hydronic radiant slabs where this assumption may not lead to an accurate estimate of the energy consumption of the system. In a hydronic radiant slab, water tubes are embedded in a slab, and hot or chilled water is circulated to meet any heating or cooling loads. The energy consumption of such a system will depend highly on the temperature of the water being sent to the slab (i.e., produced by the boiler or chiller). The temperature of the water that must be sent to the slab will depend on the spacing of the tubes, the multilayer construction of the building element, and the boundary conditions to which the construction is exposed. Thus, to accurately predict the energy consumption of such a system, a transient two-dimensional heat conduction model must be integrated with a heat balance-based simulation. This paper demonstrates the potential loss of accuracy associated with the one-dimensional radiant system models by providing a comparison of one- and two-dimensional solutions using EnergyPlus. [ABSTRACT FROM AUTHOR]