Summer air conditioning system is used in two types of weather conditions.
- Hot and wet weather conditions like Delhi, where temperature, as well as relative humidity, is high. Therefore, at such places, ‘cooling With dehumidification’ is supposed to be done by summer air conditioning system.
- Hot and dry weather conditions like Nagpur, Jalgaon etc., where temperature is high, but relative humidity is very low. Therefore, at such places, ‘cooling with humidification’ is supposed to be done.
Same summer air conditioning system can be used to supply the air having desired requirements, without changing construction of air conditioning system.
Construction of Summer Air Conditioning System
Summer air conditioning system consists of filter, cooling coil, membrane, heating coil.
Working of summer air conditioning system for hot and wet weather condition
The outside (fresh atmospheric air) is passed through a damper and then filtered for cleaning purpose i.e. to make air free from dirt, dust and from other impurities. Then the air is passed through a cooling coil (Figure 1). The cooling coil has a surface temperature less than dew point temperature of air. When the air is cooled and passed through a membrane, some quantity of water vapours associated with air are condensed due to cooling of air below its dew point temperature. Thus, the air looses the moisture in the form of condensate, (water) and is collected in the sump. Due to cooling below dew point temperature, the temperature of air decreases below the desired temperature. Therefore, this air is heated with the help of heating coil. This is done to bring the air to desired dry bulb temperature and relative humidity. The air washer system is not operative in this case of summer air conditioning.
Fig. 1: Summer air conditioning System
Working of summer air conditioning system for hot and dry weather conditions
For the regions like Jalgaon and Nagpur, the conditions in summer are hot and dry i.e. atmospheric air temperature is high, but with low relative humidity. Therefore, “Cooling with humidification” is done. After passing through filter, the air is made to pass over the cooling coil. In the previous case, the atmospheric conditions were hot and wet weather. But, in this case, we find dry weather. Therefore, the surface temperature of cooling coil is kept less than dry bulb temperature, but more than dew point temperature of air. The temperature of air is reduced by sensible cooling (1-2). In order to increase humidity, the air is passed over the air washer (spray type humidifier) system. The line 2-4 represents adiabatic humidification. In this case, the heating coil is not operative.
Fig. 2: Representation of summer air conditioning for hot and wet weather (Like Delhi)
Fig. 3: Representation of summer air conditioning for hot and dry weather (Like Nagpur, Jalgaon)