Search

This numerical study evaluates and compares four different flexibility and storage options in building energy systems (batteries, fuel switch, water tanks, and thermal building mass) in terms of potential improvements in load scheduling and energy efficiency. Using a generic modern office building with concrete core conditioning as an example, two different supply concepts (one based on a heat pump, one based on a CHP unit) are considered. A novel hybrid control concept is applied which is designed to be compatible with state-of-the-art controllers implemented in the field. The results show that batteries are the most technically attractive options in terms of grid support, efficiency and ease of implementation. Fuel switch is comparably straightforward to implement, but provides significant benefits only for the considered CHP system. Water tanks with a capacity of about two full operation hours offer nearly the same flexibility as much larger tanks, but negatively influence the efficiency of heat pump systems. The thermal building mass can be used effectively and efficiently for thermal storage, particularly in the heating season, but this is technically challenging to realize. It is shown that current electricity prices do not offer sufficient variations to stimulate grid-supportive operation. [ABSTRACT FROM AUTHOR]

The current methods used to assess the energy performance of ventilation devices do not consider all the aspects necessary for a comprehensive evaluation of decentralised ventilation concepts and can only be partially adapted to their needs. In order to improve the energy evaluation and to ensure the comparability of different systems, a calorimetric method was developed and implemented in test facilities for the evaluation of two decentralised devices: one equipped with a recuperative counter flow heat exchanger and one with a regenerative heat exchanger. This method, based on direct measurements of the heating load in an insulated test room, includes the effect of the electrical consumption of the fans on the energy performance of the ventilation devices. The calorimetric evaluation method was extended to a seasonal evaluation on the basis of a heating-degree-day method implemented for a warm, a cool and a moderate location in Europe: Athens, Strasbourg and Copenhagen. All the results are above 50% efficiency for both devices, even in Athens where the use of heat recovery ventilation is not usual. [ABSTRACT FROM AUTHOR]

Long-term monitoring campaigns were carried out in 35 German and 7 European office and administrative buildings, recording the operative room and ambient air temperature in fine time resolution. Further, short-term monitoring campaigns over two hot weeks in summer were conducted in non or partially retrofitted office buildings in Germany, built from 1960 to 1975. The buildings studied can be divided into six categories according to the cooling concept employed: without cooling, passive, air-based and water-based cooling, mixedmode cooling and full air conditioning. Thermal comfort in summer is evaluated in detail using a standardized methodology in accordance with the comfort standard DIN EN 15251:2007-08. Thermal comfort is quantified by measurements of operative room temperatures and local meteorological conditions. In addition, useful cooling energy and electricity consumption were recorded. It is clearly demonstrated that it is feasible and valuable to compare different cooling strategies based on a consistent methodology. Furthermore, this methodology can be applied in day-to-day practice in the planning, commissioning and operation of buildings since these parameters are well-established and easily accessible. [ABSTRACT FROM AUTHOR]

Highlights: [•] 135 systems from 88 companies based in 11 countries were found. [•] We present detailed analyses of many system and component related characteristics. [•] We show that solar energy is widely used as energy source for heat pumps. [•] We present technical solutions for the combination of solar thermal and heat pumps. [Copyright &y& Elsevier]

Unsichere Randbedingungen haben einen großen Einfluss auf das Ergebnis von Gebäudesimulationen. Trotzdem werden Unsicherheitsbewertungen und Sensitivitätsanalysen bisher in der Planungspraxis und auch in wissenschaftlichen Untersuchungen selten durchgeführt. In diesem Beitrag wird eine Methodik zur Unsicherheitsbewertung und Sensitivitätsanalyse für thermische Gebäudesimulationen vorgestellt. Diese wird exemplarisch angewendet, um Einsatzmöglichkeiten darzustellen. Potentielle Einsatzgebiete sind Simulationen im Planungsprozess von Gebäuden sowie eine simulationsbasierte Gebäudebetriebsanalyse. Die Anwendung der Methodik kann dazu beitragen, den Planungsprozess und den Gebäudebetrieb zu verbessern. Methodology for uncertainty and sensitivity analysis for building performance simulation. Uncertainties in simulation input have a big influence on building performance simulation results. Nevertheless, uncertainty quantification and sensitivity analysis is not commonly applied in the design practice and also in scientific research. In this paper a methodology for uncertainty quantification and sensitivity analysis is introduced. The methodology is applied to an example case to illustrate possible applications. It can be used within the design stage of buildings as well as for simulation -based building operation analysis. The methodology can improve the design process as well as building operation. [ABSTRACT FROM AUTHOR]

Abstract: This paper describes a new general method for building simulation programs which is intended to be used for the modelling of complex facades. The term ‘complex facades’ is used to designate facades with venetian blinds, prismatic layers, light re-directing surfaces, etc. In all these cases, the facade properties have a complex angular dependence. In addition to this, such facades very often have non-airtight layers and/or imperfect components (e.g. non-ideal sharp edges, non-flat surfaces, …). Therefore building planners often had to neglect some of the innovative features and to use ‘work-arounds’ in order to approximate the properties of complex facades in building simulation programs. A well-defined methodology for these cases was missing. This paper presents such a general methodology. The main advantage of the new method is that it only uses measureable quantities of the transparent or translucent part of the facade as a whole. This is the main difference in comparison with state of the art modelling based on the characteristics of the individual subcomponents, which is often impossible due to non-existing heat- and/or light-transfer models within the complex facade. It is shown that the new method can significantly increase the accuracy of heating/cooling loads and room temperatures. [ABSTRACT FROM AUTHOR]

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]

Abstract: Sustainable low-energy office buildings attempt to harness the buildings architecture and physics to provide a high quality working environment with the least possible primary energy consumption. A promising approach to condition those buildings in summer employs the utilization of the building''s thermal storage activated by natural heat sinks (e.g., ambient air, ground water or soil) through night ventilation or thermally activated building systems (TABS). However, a certain room temperature cannot be guaranteed as occupants may influence the room energy balance by window opening, internal heat gains or sun shading control. Between 2001 and 2005, monitoring campaigns were carried out over 2 or 3 years in 12 low-energy office buildings which are located in three different summer climate zones in Germany. These climate zones are defined as summer-cool, moderate and summer-hot. The weather at the building site and the room temperatures in several office rooms were monitored by different scientific teams. The raw data are processed for data evaluation using a sophisticated method to remove errors and outliers from the database and to identify the time of occupancy. The comfort in all office rooms in each building is evaluated separately. For data presentation, these separate comfort votes per office room are averaged using the median instead of the arithmetic mean in order not to overestimate extremely cold or hot room temperatures. A comfort evaluation in these 12 low-energy office buildings indicates clearly, that buildings which use only natural heat sinks for cooling provide good thermal comfort during typical and warm summer periods in Germany. However, long heat waves such as during the extreme European summer of 2003 overstrain passively cooled buildings with air-driven cooling concepts in terms of thermal comfort. [Copyright &y& Elsevier]

Abstract: To gain access to information on energy use in office buildings, the German Federal Ministry for Economy launched an intensive research and demonstration programme in 1995. In advance of the 2002 EU energy performance directive a limited primary energy coefficient of about 100kWhm−2 a−1 as a goal for the complete building services technology was postulated (HVAC+lighting) for all demonstration buildings to be supported. A further condition was that active cooling be avoided. Techniques such as natural or mechanical night ventilation or heat removal by slab cooling with vertical ground pipes as well as earth-to-air heat exchangers in the ventilation system were applied. An accompanying research was established to keep track of the results and the lessons learned from about 22 demonstration buildings realized and monitored until the end of 2005. As one outcome this paper summarises the energy performance of a selection of characteristic buildings together with an overview on the summer thermal comfort situations achieved. The research program will proceed during the next five years. Detailed reports and future results may be downloaded from the internet: www.enbau-monitor.de. [Copyright &y& Elsevier]

Abstract: This study focuses on the impact of the meteorological environment and the building''s thermal inertia on the indoor temperature performance in a passively cooled office building with night ventilation. Data from a long-term monitoring campaign and short-term measurements are used to identify the correlation between outdoor and indoor temperature in a building under ordinary use and to derive the energy balance of an office room. Temperature performance and energy balance are merged in a comprehensive thermodynamic model, which takes steady-state conditions, short-term and long-term dynamics into account. In contrast to extensive simulation studies, the presented method is based on a straightforward mathematical model using Fourier analysis of temperature time series and an energy balance model, which focuses on fundamental information. [Copyright &y& Elsevier]

In moderate climates, one promising approach to reduce the energy demand of office buildings for air conditioning without reducing comfort is passive cooling by night ventilation. The office building of DB Netz AG in Hamm (Germany) has been designed, constructed and monitored for a long period in the framework of the German research programme, “Solar Optimised Buildings”, SolarBau for short. Monitored data of room and ceiling temperatures in 12 office rooms, supply air flow rate and temperature in these office rooms, electricity consumption for each office room, climate and air temperatures in an adjacent atrium are evaluated by a new method for analysis which deals with short-term and long-term measurements and building simulation. The monitored data from the office building, which is used as such, are complemented by information from the building management system about the position of louvers and the shading devices. The contribution of simulation tools to the design of buildings with passive cooling by night ventilation is evaluated by a comparison between monitored data and simulation for a long period. [Copyright &y& Elsevier]

At the new institute building of Fraunhofer ISE, both mechanical and free night ventilation is used for passive cooling of the offices. The results from a long-term monitoring show, that room temperatures are comfortable even at high ambient air temperatures. In two offices, experiments were carried out in order to determine the efficiency of night ventilation dependent on air change rate, solar and internal heat gains. The aim is to identify characteristic building parameters and to determine the night ventilation effect with these parameters. The experiments (one room with and one without night ventilation) are evaluated by using both a parametric model and the ESP-r building simulation programme. Both models are merged in order to develop a method for data evaluation in office buildings with night ventilation and to provide a simple model for integration in a building management system. [Copyright &y& Elsevier]

The building and transportation sectors in the EU are progressing towards the zero-energy/emission levels according to the EU 2050 roadmap while the H 2 vehicles have recently started to be commercialized. Based on these backgrounds, this paper focuses on the investigation of a hybrid zero-energy system which consists of a zero-energy building and a H 2 vehicle integrated H 2 system. The focused aspects in this paper are the impact of the ground source heat pump (GSHP), the Finnish and German climate conditions, and the on-site PV and wind turbine capacities and their mix on system performance. The parametric analyses based on these aspects are conducted in the TRNSYS simulation environment. The results show that the use of a GSHP helps realize the net zero-energy balance with less local generation, while improving the overall matching capability with marginal influence on the utilization of the cogenerated heat. Moreover, the Finnish condition has a clear preference on the wind based net zero-energy system, whereas the German condition has a preference on the solar based system. Correspondingly, the optimal mix of PV and wind turbine for the net zero-energy cases occurs when the PV generation percentage reaches 20% and 60% under Finnish and German conditions, respectively. [ABSTRACT FROM AUTHOR]

Gebäude können einen Beitrag zur Energiewende leisten, indem sie bevorzugt Wind‐ und Sonnenstrom zum Heizen und Kühlen nutzen und die Energie in thermischer Form im Gebäude zwischenspeichern. Dieser Fachaufsatz analysiert die heutigen und zukünftigen Anforderungen an “netzdienliche” Gebäude und stellt ein Konzept vor, mit dem sich die Gebäudemasse selbst als Wärme‐ und Kältespeicher nutzen lässt. Das Konzept basiert auf TABSOLAR genannten, durchströmbaren Bauteilen aus Ultrahochleistungsbeton (UHPC) mit eingeformten FracTherm®‐Hohlraumstrukturen, welche sich thermisch aktivieren lassen. Aufgrund des innovativen Fertigungsverfahrens lassen sich sehr dünne Bauteile mit einer entsprechend geringen thermischen Trägheit realisieren. Im vorgestellten Anwendungsbeispiel werden TABSOLAR‐Elemente als deckeninstalliertes schnelles Wärmeübergabesystem in Verbindung mit einem thermisch mittels Wärmedämmung von der Zone getrennten, thermoaktiven Bauteil‐System (TABS) genutzt, dessen große thermische Masse als Wärmespeicher dient. Erste Simulationen zeigen, dass das gewählte Konzept einen Übergang zu netzdienlichem Betrieb der Wärmeversorgungsanlagen auf Basis von Wärmepumpen bei einer gleichzeitigen wesentlichen Verbesserung des Raumkomforts ermöglicht. Buildings as grid‐supportive heat storages – Requirements to buildings of the future Buildings can contribute to the Energy Transition in Germany by using predominantly electricity generated by Wind and PV plants for heating and cooling and by storing energy in thermal form decentrally in the building. This paper analyzes present‐day and future requirements to ”grid‐supportive" buildings and presents a concept for using the building mass as a heat and cold storage. The concept is based on so‐called TABSOLAR construction elements made of Ultra High Performance Concrete (UHPC) which can be thermally activated via molded FracTherm® capillary fluid canals. Due to the innovative manufacturing process, very thin and thermally light components can be realized. In the example of use presented as part of this paper, TABSOLAR elements are used as a fast, ceiling‐mounted heat delivery system in combination with a thermally insulated thermally activated building System TABS, whose large thermal inertia serves as a heat storage. First simulations show that the chosen concept allows for a transition to ”grid‐supportive" heat generation using heat pumps and simultaneously improves thermal comfort significantly. [ABSTRACT FROM AUTHOR]

In the residential sector, heat pumps are applied for domestic hot water and space heating. Simulations are widely used for general research in the field of heat pumps and to some extend to plan such installations. The advantages are low expenditure of time and costs compared to laboratory or field tests. Validation of simulation models is mandatory to guarantee a sufficient quality. In the presented paper, the field monitoring results of five ground-source installations are utilised for the validation of a black-box heat pump model. The model is similar to TRNSYS Type 201, but implemented in IDA ICE and then modified to handle the difficulties caused by non-standard mass flow and rampant polynomials. As overall result, deviations between 1% and 32% regarding modelled and measured efficiency are seen on monthly basis. The overall result appears as convincing, taking into account typical inaccuracies of laboratory and field tests as well as tolerances during heat pump production. As a side effect, the influence of standby consumption was quantified. For the five presented installations, standby amounts to fractions between 2 and 5% of the annual electricity consumption of the heat pump units. [ABSTRACT FROM AUTHOR]

Durch den steigenden Anteil fluktuierender erneuerbarer Energieträger im deutschen Energiesystem wird neben der Höhe des Stromverbrauches auch das zeitliche Bezugsprofil immer wichtiger. Demand-Side-Management elektrischer Verbraucher ist ein viel diskutiertes Thema - auch im Bereich der Gebäudetechnik. Daher stellt sich die Frage, welche Anforderungen an das Stromverbrauchsverhalten für einen 'netzdienlichen' Betrieb gestellt werden und wie sich die 'Netzdienlichkeit' gebäudetechnischer Anlagen quantitativ erfassen lässt. In dieser Arbeit werden EEX Day-ahead-Preis, Residuallast, kumulierter Energieverbrauch (KEV) des deutschen Strommixes sowie der Anteil von Wind und Photovoltaik an der Nettostromerzeugung der Jahre 2010 bis 2013 im Hinblick auf saisonale und tageszeitliche Strukturen untersucht. Die Auswertung zeigt, dass bezüglich des EEX-Preises und der Residuallast die Nachtstunden zwischen 1:30 Uhr und 4:00 Uhr den günstigsten Bezugszeitpunkt darstellen und dass die größten Tagesschwankungen im Winter auftreten. Dem gegenüber steht die Beobachtung, dass der Strommix insbesondere im Frühling und Sommer mittags zwischen 12:30 und 14:30 Uhr einen etwa viermal höheren Anteil aus Wind- und Photovoltaikanlagen als nachts aufweist und mit einem rund 20 % geringeren kumulierten Energieverbrauch erzeugt wird. Weiterhin wird eine Bewertungskennzahl R definiert, mit welcher sich das Strombezugsverhalten für beliebige Verbraucher, Betrachtungszeiträume und stromnetzbasierte Vergleichsgrößen quantitativ und dimensionslos bewerten lässt. Anhand von gemessenen Stromverbrauchsdaten für die Wärme- und Kälteerzeuger eines Bürogebäudes wird beispielhaft gezeigt, wie die neue Kennzahl die bekannten Größen zur energetischen Bewertung von Gebäuden ergänzen kann. Grid-interactivity of buildings: analysis and comparison of grid based reference parameters and definition of an evaluation number. The fraction of Renewables in the German energy system is rising quickly. As a consequence, not only the quantity of electricity consumption, but also the time profile of the electricity demand will be increasingly important in the future. Demand-Side-Management is more relevant than ever, also in the building sector. However, it is still uncertain what the requirements to 'grid-interactive' electricity consumers are and how 'grid-interactivity' can be measured quantitatively. This work analyzes the German electricity mix of the year 2010 to 2013 in terms of the EEX Day-ahead price, the residual load, the cumulative energy consumption (KEV) as well as the fraction of Wind and PV in the electricity mix with respect to the seasonal and intraday structures of these quantities. The daily profiles of the EEX price and residual load suggest that electricity consumption should be shifted to the night hours between 1.30 a.m. and 4.00 a.m. To the contrary, in the noon hours between 12.30 p.m. and 2.30 p.m., the fraction of electricity from wind and photovoltaics in the electricity mix is about four times higher than at night and electricity production is roughly 20% less resource demanding in terms of the cumulative energy consumption. Furthermore, a dimensionless number R is defined which allows a quantitative evaluation of the temporal structure of electricity consumption with respect to any consumer, observation period and grid-based reference quantity. The new number is applied to real monitoring data in an exemplary manner to show how it can complement the established performance indicators of energetic building analysis. [ABSTRACT FROM AUTHOR]

Abstract: A detailed analysis of the heating and cooling performance of environmental heat sources and sinks is presented for 12 low-energy buildings in Germany. In particular, the analysis focuses on the given temperature levels and the efficiency performance of the environmental heat sources and sinks in summer and winter. The investigated buildings employ environmental heat sources and sinks – such as the ground, groundwater, rainwater and the ambient air – in combination with thermo-active building systems (TABS). 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/(mnet 2 a) as a target for the complete building service technology (HVAC and lighting) was postulated for all buildings presented. With respect to this premise, comprehensive long-term monitoring in fine time-resolution occurred over a period from two to five years. An accompanying commissioning of the building performance took place. Measurements include water supply and return temperatures of the environmental heat sources/sinks, the generated heating and cooling energy, efficiencies of the system, and local climatic site conditions. The comparative evaluation of the systems in all buildings identifies weak points and success factors of the plant. Besides, it characterizes the single component and points out further potential for optimization measures. The annual efficiency performance of the geothermal heat sources and sinks results in a seasonal performance factor of 8–10kWhtherm/kWhend, where the end energy use is electricity. The ground, groundwater, rainwater and even the ambient air constitute efficient heat sources/sinks. Energy is needed only for distributing the heat and cold and not for its generation. The choice of suitable plant components, the accurate design of the hydraulic system and the correct dimension of the environmental heat source/sink play a central role in achieving higher efficiencies. [Copyright &y& Elsevier]

Abstract: This article investigates building thermal mass control of commercial buildings to reduce utility costs with a particular emphasis on the individual impacts of both adaptive comfort criteria and of heat waves. Recent changes in international standards on thermal comfort for indoor environments allow for adaptation to the weather development as manifested in comfort criteria prEN 15251.2005 and NPR-CR 1752.2005 relative to the non-adaptive comfort criterion ISO 7730.2003. Furthermore, since extreme weather patterns tend to occur more frequently, even in moderate climate zones, it is of interest how a building''s passive thermal storage inventory responds to prolonged heat waves. The individual and compounded effects of adaptive comfort criteria and heat waves on the conventional and optimal operation of a prototypical office building are investigated for the particularly hot month of August 2003 in Freiburg, Germany. It is found that operating commercial buildings using adaptive comfort criteria strongly reduces total cooling loads and associated building systems energy consumption under conventional and building thermal mass control. In the case of conventional control, total operating cost reductions follow the cooling loads reductions closely. Conversely, the use of adaptive comfort criteria under optimal building thermal mass control leads to both lower and slightly higher absolute operating costs compared to the optimal costs for the non-adaptive ISO 7730. While heat waves strongly affect the peak cooling loads under both conventional and optimal building thermal mass control, total cooling loads, building energy consumption and costs are only weakly affected for both control modes. Passive cooling under cost-optimal control, while achieving significant total cost reductions of up to 13%, is associated with total energy penalties on the order of 1–3% relative to conventional nighttime setup control. Thus, building thermal mass control defends its cost saving potential under optimal control in the presence of adaptive comfort criteria and heat waves. [Copyright &y& Elsevier]

A new method for assessing the grid interaction of a building’s electricity consumption and generation is presented. It consists of the Grid Support Coefficients GSC abs and GSC rel . GSC abs “weights” the electricity consumption profile with a time-resolved reference quantity which expresses the availability of electricity in the public grid (here: stock electricity price, residual load, cumulative energy consumption or fraction of wind and PV in the electricity mix). GSC rel relates GSC abs to the worst and best achievable values on a scale of −100 to 100 in order to increase the comparability of the results. The new evaluation method is applied to analyze the electricity consumption and/or production of 52 different energy supply systems in buildings, where detailed monitoring data are available. These examples include twelve heat pumps or chillers in office buildings, 38 heat pumps in residential buildings and two combined heat and power units (CHP) in multi-family buildings, all located in Germany. The in-depth analysis shows that the analyzed present-day buildings predominantly consume electricity at times with a low or average electricity availability. Optimal scheduling of all heat pumps could flatten the residual load significantly. In order to achieve this, thermal storages several times larger than the ones currently installed would be required. [ABSTRACT FROM AUTHOR]

Heat pumps are expected to play a central role in decarbonizing heat supply, but face challenges in existing buildings due to high temperature requirements of existing radiator systems. This paper links the performance analysis of heat pump systems with methods to reduce temperatures of the space heating circuit. Field data and system simulations of air and ground source heat pumps show a linear correlation between the seasonal performance factor SPF and the mean heat pump temperature over a wide temperature range. Every Kelvin of reduced heat pump temperature increases the SPF by 0.10–0.13 points. Applied methods to reduce heating temperatures are demonstrated at existing multi-family buildings. Thermal insulation reduces the building's heat load, allowing a reduction of heating temperatures with the existing radiators. A further temperature reduction is achieved by analyzing the required heating power per room and identifying critical, undersized radiators. In a studied building, the selective exchange of only 7% of all radiators is sufficient to reduce heating temperatures from 75 °C/60 °C–55 °C/45 °C. This corresponds to a reduction of the electricity consumption by 40–42%. However, the potential of these methods is specific for each building and depends particularly on its renovation state and installed radiator capacity. Nonetheless, an energy- and cost-efficient operation of heat pumps retrofitted in existing radiator heating systems is viable, if following the proposed system design method linking heat pump performance and reduction of space heating temperatures. • Performance analysis of retrofit heat pumps by field tests and system simulations. • Effect of heating temperatures on heat pump performance is analyzed. • Measures to reduce temperatures are applied in existing multi-family buildings. • Selective exchange of 7% of all radiators reduces electricity consumption by 40%. • Methods improve energy and cost-efficient operation of heat pumps in existing buildings. [ABSTRACT FROM AUTHOR]

In the face of the broad political call for an "energy turnaround", we are currently witnessing three essential trends with regard to energy infrastructure planning, energy generation and storage: from planned production towards fluctuating production on the basis of renewable energy sources, from centralized generation towards decentralized generation and from expensive energy carriers towards cost-free energy carriers. These changes necessitate considerable modifications of the energy infrastructure. Even though most of these modifications are inherently motivated by geospatial questions and challenges, the integration of energy system models and Geographic Information Systems (GIS) is still in its infancy. This paper analyzes the shortcomings of previous approaches in using GIS in renewable energy-related projects, extracts distinct challenges from these previous efforts and, finally, defines a set of core future research avenues for GIS-based energy infrastructure planning with a focus on the use of renewable energy. These future research avenues comprise the availability base data and their "geospatial awareness", the development of a generic and unified data model, the usage of volunteered geographic information (VGI) and crowdsourced data in analysis processes, the integration of 3D building models and 3D data analysis, the incorporation of network topologies into GIS, the harmonization of the heterogeneous views on aggregation issues in the fields of energy and GIS, fine-grained energy demand estimation from freely-available data sources, decentralized storage facility planning, the investigation of GIS-based public participation mechanisms, the transition from purely structural to operational planning, data privacy aspects and, finally, the development of a new dynamic power market design. [ABSTRACT FROM AUTHOR]

Abstract: This article presents a simulation study comparing the primary energy and comfort performance of ventilation assisted thermo-active building systems (TABS) relative to a conventional all-air (VAV) system in a compact office building featuring good thermal envelope performance, heat recovery, and solar gain control for the continental climate of Omaha, Nebraska with pronounced heating and cooling periods. TABS heating is accomplished using a geothermal heat pump and TABS cooling using a geothermal heat exchanger without an additional vapor compression cycle required. It was found that the coordination of the TABS and VAV systems is crucial, i.e., supply air temperature and active layer temperature setpoints and reset schedules greatly affect the performance of the overall system. The small contribution of TABS in the heating case shows the need for the adaptation of the ventilation system configuration to the TABS system. Annual cooling energy demand for the ventilation assisted TABS is higher than for the pure VAV system, which is due to lower occupied period room operative temperatures and thus a higher comfort provided. While a 4% useful energy penalty for the combined TABS/VAV was recorded, the VAV case requires 20% more delivered energy than the TABS case because of the displacement of compressor driven coil loads with low-exergy cooling through the ground heat exchanger in the TABS case. A primary energy intensity of 189kWh/m2 a was recorded for the TABS case; in contrast, the conventional all-air (VAV) equipped building incurs a primary energy intensity of 229kWh/m2a, which represents a penalty of 20%. Clear advantages of the TABS approach can be observed with respect to thermal comfort: during summer cooling periods, the mean radiant temperature of the TABS case is on average 2K below that of the VAV case. Moreover, the VAV system is associated with a fairly constant predicted mean vote (PMV) value of 0.75, which is quite warm, while the TABS equipped system reveals an average of 0.56, which results in only 12% instead of 17% of people dissatisfied. Based on these results, ventilation assisted thermo-active cooling systems appear to be a very promising alternative to conventional all-air systems offering both significant primary energy as well as thermal comfort advantages provided the TABS is mated with low-exergy heating and cooling sources. [Copyright &y& Elsevier]

Abstract: The investigation on the effect of painted facades with spectrally selective properties on the energy balance of a building is made by comparing real measured data from an outdoor test of facade samples with data calculated using the ESP-r simulation program. The following factors were investigated: influence of solar radiation, calculated with a solar model, the absorption of direct solar radiation as a function of the angle of incidence, IR radiation exchange and the influence of heat loss caused by convection. During this investigation, it was determined that the influence of solar radiation and especially the heat loss caused by convection are the most dominant influences on the examined energy balance of a building. After adapting the simulation program in order to simulate the data correctly, the influence of selective facades is investigated using an office model as an example. In the case of the location of Freiburg, Germany, two different types of outer walls are investigated and described in this publication: A well-insulated wall with a U-value of 0.42W/(m2 K) and a poorly insulated wall with 1.95W/(m2 K). The savings in the heating demand are higher in the case of poorly insulated walls than in well-insulated walls. In contrast to this effect, the cooling demand increases nearly in the same way for both types of walls. The tendency for condensation is also weakened, as is documented in [4]. [Copyright &y& Elsevier]