Solar-Active-Houses – Dynamic System Simulations to Analyze Building Concepts with High Fractions of Solar Thermal Energy

Abstract

In the German national research and development project "HeizSolar" the building concept of Solar-Active-Houses is analyzed. The concept allows for a high fraction of solar thermal energy of more than 50% of the total heat supply. Within the project nine existing buildings have been monitored since the beginning of the heating period of 2011. The technology applied for this kind of supply concept has been introduced in [1, 2]. Based on the data obtained from the in-situ monitoring, typical operation conditions have been identified and analyzed in [3]. The measured data was also used to derive parameters to calibrate a dynamic system simulation model for Solar-Active-Houses [4]. The elaborated model focuses on the performance of the solar thermal collector as well as the solar circuit. What is more, the dynamic interaction between the solar thermal heat generator and the auxiliary heating systems as well as the heat distribution system are incorporated in detail. Finally the diffuse heat flux resulting of the integration of large hot water storage tanks into the building envelope is implemented to the model. This model is applied in the following to analyze the general thermal behavior of the supply concept and to derive optimization potentials. In detail the systems performance in regard to different types of heat transferal systems for space heating is demonstrated. Also the dimensioning in regard to the key parameters of collector area and the thermal capacity of the storage system consisting of a hot water storage tank are stated. et al. / Energy Procedia 70 ( 2015 ) 652 -660 653 Nomenclature A ap ST collector aperture area (m²) f sol fraction of ST energy (-) Q AuxH useful heat delivered by the AuxH system (kWh) Q DHW useful heat demand for DHW preparation (kWh) Q loss,use useful heat losses of the hydraulic components like piping and the TES (kWh) Q SH,AuxH useful SH demand covered by ST including a fraction of AuxH (kWh) Q SH,dmd gross SH demand of the building at a constant room temperature of 20°C (kWh) Q SH,solar SH demand covered completely by ST (kWh) q TES relative charging level of TES (-) TES,sim T simulated mean temperature of TES (°C) TES,ref T reference mean temperature of TES (88°C) UA TES overall heat-transfer coefficient of TES (W/K) V TES effective volume of TES (m³)

Demonstration of a solar combi-system utilizing stable supercooling of sodium acetate trihydrate for heat storage

“…Europe. Water tanks have been used for this purpose [10,11], but large storage volumes were necessary to compensate for sensible heat losses.…”