Free cooling

The interest in phase change materials (PCMs) as a solution for thermal energy storage has been growing for the last decades. It is clear that PCMs are promising for reducing the summer heat peaks without increasing the energy demand for cooling. A new modular, reversible, lightweight retrofitting system was developed and integrated in a real size experimental test cell.

Earlier field measurements in Low Energy Buildings have shown that excess temperatures can easily occur during summertime in well-insulated houses, also in northern part of Europe. If a ground source heat pump is used for heating and there is a bidirectional ventilation system, the borehole can be used for free cooling in summertime and the chilled air can be distributed by the ventilation system. In this study, a simulation of a single family nZEB located in the Swedish city Gothenburg was conducted.

An experimental analysis of the night ventilation technique for cooling in buildings, was performed in a test cell with the aim of establish the potential of this technique in two scenarios: a) when the air-stream is in poor contact with the thermal mass and b) when the air-stream is in close contact with the thermal mass of the test cell. The test cell is a small one-room building equipped with instrumentation for measurement and control the night ventilation following a strategy based in the values of indoor and outdoor temperatures.

This paper aims at pointing out that how a District Cooling system can be a more energy efficientsolution compared with a decentralized cooling solution. In order to give a fair comparison, the authorapplies equivalent electric power coefficient of performance. This comparison approach will beinstructive for designing an energy efficient cooling solution in China.Firstly, the paper gives the definition, components and possible energy source of a District CoolingSystem.

Nella ventilazione a dislocamento, l’aria fresca e a bassa velocità è immessa direttamente nella zona occupata a livello del pavimento; essa quindi si muove verso l’alto per effetto delle forze di galleggiamento alimentate dai pennacchi termici all’intern