Applicability of high-temperature cooling systems in different European countries from the view of the condensation risk

Due to the different approaches in determining the ventilation airflow rate per person for workspaces,where high-temperature air conditioning systems are used for air conditioning,problems with the condensation of water vapour on the cold surfaces of the system can occur.The article analyses the risk of condensation in various European cities using the available climatic data.Systems with cooling ceilings and cooling beams with a ventilation device operating in parallel are taken into account.Different ventilation airflow rates per person were analysed.On the example of a room equipped with high-temperature cooling,an energy simulation calculation is performed,which includes a ventilation and air-conditioning system with the possibility of capacity control.It is clear from the results that the condensation of water vapour can be prevented by technical measures at the cost of reducing the cooling capacity,which can affect the achievement of the thermal comfort of those present.In the end,suitable solutions are discussed,which should already be adopted at the time the device is designed so that the risk of condensation is not a major obstacle in the operation of these energy-efficient systems.An irreplaceable role in the operation of high-temperature cooling systems is played by a measurement and control system with a suitable algorithm to prevent condensation.

Simulation of thermal and humid environment of rural residence envelope inner surface during the plum rains season in Changsha China

The Plum Rains Season(PRS)has the typical characteristics of outdoor air temperature dramatic changes and high air humidity in the hot summer and cold winter region in China.Even if the indoor heat source and moisture production is constant,when the outdoor air temperature rises rapidly during high air humidity PRS,the build-ing envelope temperature heats up much more slower than the indoor air temperature and therefore the wall surface temperature is lower than the indoor air dewpoint which leads to condensation phenomenon,resulting in deterioration of insulation performance,mouldy walls,deterioration of indoor air quality.At present,there is a lack of research on the factors affecting condensation in rural residence during PRS.This paper evaluates the impact of occupants’habit of window opening modes and building construction parameters on the building envelope surface condensation in Changsha during PRS.Using Designer’Simulation Toolkit(DeST)simulated and analysed the impact of key parameters such as window-to-wall ratio,exterior wall reflectivity,window opening mode(open/close),and external wall insulation on the building indoor thermal and humid environment.The condensation risk X is proposed to evaluate the condensation possibility on the building envelope’s inner sur-face.The results show that from the perspective of anti-condensation:The rural residential building in Changsha should balance the window-wall ratio against better natural lighting;Keeping windows closed during PRS can effectively alleviate the condensation problem while the insulation in the external wall layer could aggravate the condensation.