Patent ID: 8397522

Claim:
A system for controlling environmental conditions in a space, comprising: a vapor-compression refrigerant loop including at least a 2-speed compressor, a condenser, a reheat coil, an expansion device, a receiver and an evaporator coil; a variable speed air mover that drives a first air stream sequentially from a space across the evaporator and a reheat coil; a plurality of valves disposed within the vapor-compression refrigerant loop; and a controller operably connected to the vapor-compression refrigerant loop, the air mover and the plurality of valves, wherein the condenser discharges heat to an environment outside the space, and the controller controls a plurality of discrete stages with differing rates of sensible cooling and latent cooling, the controller selects from among the plurality of stages based on at least one of sensed environmental conditions relative to user input temperature and humidity settings, the controller being configured to select a first stage of the plurality of discrete stages that provides maximum latent cooling of the first air stream while minimizing sensible cooling and sensible heating of the first air stream, and in the first stage, the controller controls the operation of the valves to cause refrigerant to (i) flow through the reheat coil, (ii) then drain from the reheat coil to the receiver, and (iii) then flow from the receiver to the expansion device, the controller being further configured to select a second stage that provides enhanced latent cooling with moderate sensible cooling of the first air stream, and in the second stage the controller controls the operation of the valves to cause the refrigerant to (i) flow through the reheat coil; and (ii) then bypass the receiver and flow to the expansion device, the sensible cooling corresponds to reducing a measured temperature of the first air stream, the sensible heating corresponds to increasing a measured temperature of the first air stream, and the latent cooling corresponds to reducing a humidity of the first air stream.