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Abstract: Dwellings represent more than 40% of final energy consumption in France. They also present the highest potential of energy savings, while using technology already substantiated, without huge investments, in contrast to other sectors. Ventilation is one of the main sources of heating loss in buildings, so recovering heat from exhaust air could reduce significantly heating loads. In airtight and well insulated buildings, heat recovery ventilation (HRV) systems are often recommended to save heat energy. However, these savings should be balanced against the electrical power requirements of the fans. A HRV unit is modeled, using TRNSYS, and studied in order to characterize its annual performance when integrated into residential and commercial low energy buildings. The energy performance of HRV is compared to one of the standard ventilation systems. This comparison is based on the heating, cooling and ventilation primary energy consumption for different climatic zones. It is found that the adequacy of using HRV system depends on the building types, the heating loads and ventilation device characteristics. A sensitivity analysis by simulation is undertaken to investigate the influence of exchanger efficiency and specific fan power on the global energy performance of the HRV system. [Copyright &y& Elsevier]

Abstract: A desiccant wheel model has been developed in the aim to be adapted to building simulation tools. This model fulfils several criteria such as simplicity of parameterization, accuracy, possibility to characterize the equipment under all operation conditions and low computation time. The method of characteristics has been applied to the heat and mass transfer partial differential equations. This transformation provides new equations which are similar to those of a rotary heat exchanger. Then, the model is described by the Effectiveness-NTU method and it is identified from only one nominal rating point. The model has been compared to experimental and manufacturers’ data for a broad range of operating conditions. A good agreement has been found. [Copyright &y& Elsevier]

Abstract: A desiccant-wheel behavioural model has been developed. This model fulfils several criteria, such as simplicity of parameterization; accuracy; ability to characterize the equipment behaviour under all operation conditions; and short computation time. The method of characteristics has been applied to the heat-and-mass transfer partial-differential equations. This transformation provides equations which are similar to those of a rotary heat-exchanger. Then, the model is described by the effectiveness-NTU method and identified from only one nominal-rating point. The model predictions have been compared with experimental and manufacturers’ data for a broad range of operating conditions. Good agreement has been found. [Copyright &y& Elsevier]

A simplified model for indirect cooling towers behaviour is presented. The model is devoted to building simulation tools and fulfils several criteria such as simplicity of parameterisation, accuracy, possibility to model the equipment under various operation conditions and short computation time. On the basis of Merkel''s theory, the model is described by using the Effectiveness-NTU method. The model introduces only two parameters, air-side and water-side heat-transfer coefficients which can be identified from only two rating points, data easily available in manufacturers'' catalogues. Thus, the model allows one to estimate energy and water consumptions under different operating conditions such as variable wet-bulb temperatures or variable airflow rates. [Copyright &y& Elsevier]

Highlights: [•] Six heating systems are compared in a low energy house for different climates. [•] MCHP and electric HPs are more efficient than gas or wood boilers and absorption HP. [•] The absorption HP would be the most efficient if small size products were developed. [•] The merit order of electric heat pumps drops with the current oversizing practice. [•] The intermittent heating has a limited interest in low energy houses. [ABSTRACT FROM AUTHOR]