Energy conservation enthalpy control system and sensor therefor

In combination, a control apparatus for controlling both a cooling system which includes a cooling source, a cooling system, and controllable means coacting with said cooling source and said cooling system to control the rate of cooling thereof and an air damper system which includes an outside air damper, a return air damper, and damper control means including an air operated motor for controlling the operation of said dampers, said control apparatus including:

• first sensing means for sensing the outside air enthalpy and providing a first pressure signal representative thereof;
• second sensing means for sensing return air enthalpy and providing a second pressure signal representative thereof;
• and
• comparing means including a differential pressure switch for comparing said first pressure signal and said second pressure signal to cause said damper control means to operate to close at least partially said return air damper and open at least partially said outside air damper when said outside air enthalpy is lower than said return air enthalpy.

In combination, a control apparatus for controlling both a cooling system which includes a cooling source, a cooling system and controllable means coacting with said cooling source and said cooling system to control the rate of cooling thereof and an air damper system which includes an outside air damper, a return air damper, and damper control means for controlling the operation of said dampers, said control apparatus including:

• first sensing means for sensing the outside air enthalpy and providing a first signal representative thereof;
• second sensing means for sensing return air enthalpy and providing a second signal representative thereof, at least one of said first and said second sensing means comprising:
• a. a housing which includes means for passing sampled air through said housing and sump means for collecting a body of water,
• b. means cooperating with said housing for filtering said sampled air to remove physical contaminants from said sampled air,
• c. mixing means for intimately mixing and contacting water from said sump means and said sampled air under conditions closely approximating adiabatic saturation,
• d. means for recirculating said water, said recirculating means including a pump for pumping water from said sump means to said mixing means,
• e. sensing means including a sensing element in said water in said sump means for sensing the temperature of said water when the temperature of said air and water are in equilibrium to provide an output signal representative of the wet bulb temperature of said sampled air, and
• f. transmitter means for transmitting a signal representing said wet bulb temperature;
• and
• comparing means for comparing said first signal and said second signal to cause said damper control means to operate to close at least partially said return air damper and open at least partially said outside air damper when said outside air enthalpy is lower than said return air enthalpy.