Diversification of load
As was indicated earlier, if reductions in the sensible gain to a conditioned space are dealt with by elevating the supply air temperature through the use of reheat, no corresponding reduction in refrigeration load will occur. All the air supplied is cooled to a fixed dew point and the false load imposed by the reheat equals the reduction in sensible gain to the room.
Operating in opposition and thermostatically controlled in groups for each zone (a)
Ratio line for zone 2 having sensible loss and latent gain
Fig. 8.9 The plant layout and psychrometry for a multi-zone unit.
If methods are adopted such as the use of face and by-pass dampers, which raise the supply air temperature as the sensible gain diminishes without wasting any cooling, then the refrigeration load will not necessarily involve the sum of the maximum sensible gains to two or more rooms conditioned.
If a plant which separates the dehumidifying and fresh-air load from the main bulk of the sensible load is used, then reductions in sensible gain are dealt with by reducing the secondary sensible cooling, rather than by cancelling cooling with reheat.
Posted in Engineering Fifth Edition