System and Method for Compressor Optimization and System Cycling

Abstract

A system and method are described for conserving energy in HVAC systems. During certain temperature requests, ambient air can be supplied to a conditioned space and the HVAC compressor can be turned off to conserve power. During certain temperature requests, supply air can be adjusted through cycling of heating or cooling elements to conserve power and maintain desired space temperature. In various embodiments, supply air temperature, coil temperature, cabinet temperature and other values can be monitored for their effect on cooling and/or heating, and taken into account for determining how to best cool or heat a conditioned space.

What is claimed is: 
     
         1 . A method for operating an HVAC system comprising a heat exchanging coil, one or more compressors, and an HVAC controller, the method comprising:
 receiving, at the HVAC controller, a temperature request for a climate controlled space;   determining a basis air temperature of the climate controlled space using at least one sensor in the climate controlled space;   determining an ambient air temperature;   determining that ambient air can be used to fulfill the temperature request;   restricting operation of a compressor;   supplying ambient air to the climate controlled space;   determining a supply air temperature using a sensor in the supply airstream;   determining a current temperature of the climate controlled space; and   adjusting an operation of the HVAC system based on at least the determined supply air temperature, the determined current temperature of the climate controlled space, and the determined ambient temperature.   
     
     
         2 . The method of  claim 1  further comprising:
 determining a humidity level in the space; and 
 adjusting an operation of the HVAC system based on at least the determined humidity level. 
 
     
     
         3 . The method of  claim 1  further comprising;
 determining a coil temperature and an HVAC cabinet temperature; and 
 adjusting an operation of the HVAC system based on at least one of the determined coil temperature and the determined HVAC cabinet temperature. 
 
     
     
         4 . The method of  claim 1  wherein restricting operation of a compressor comprises turning off the compressor. 
     
     
         5 . The method of  claim 1  wherein adjusting an operation of the HVAC system comprises adjusting an amount of refrigerant. 
     
     
         6 . The method of  claim 1  wherein adjusting an operation of the HVAC system comprises adjusting an operation of a heat exchanger. 
     
     
         7 . The method of  claim 1  wherein adjusting an operation of the HVAC system comprises adjusting an operation of an enthalpy wheel. 
     
     
         8 . The method of  claim 1  further comprising:
 determining a pressure level; and 
 adjusting an operation of the HVAC system based on the determined pressure level. 
 
     
     
         9 . A method of operating an HVAC system comprising a heat exchanging coil, one or more compressors, and an HVAC controller, the method comprising:
 determining a temperature of a climate controlled space;   receiving a temperature request for the climate controlled space;   activating one or more compressors;   determining a temperature of a supply air;   determining if the temperature of the supply air has reached a predetermined level;   if the temperature of the supply air has not reached the predetermined level, then continuing with normal compressor operation; and   if the temperature of the supply air has reached the predetermined level, then turning compressors off and on to modulate the supply air provided to the climate controlled space to satisfy the temperature request.   
     
     
         10 . The method of  claim 9  further comprising:
 determining a humidity level in the space; and 
 adjusting an operation of the HVAC system based on at least the determined humidity level. 
 
     
     
         11 . The method of  claim 9  further comprising;
 determining a coil temperature and an HVAC cabinet temperature; and 
 adjusting an operation of the HVAC system based on at least one of the determined coil temperature and the determined HVAC cabinet temperature. 
 
     
     
         12 . The method of  claim 10  wherein adjusting an operation of the HVAC system comprises adjusting an airstream of return air. 
     
     
         13 . The method of  claim 10  wherein adjusting an operation of the HVAC system comprises adjusting an amount of refrigerant. 
     
     
         14 . The method of  claim 11  wherein adjusting an operation of the HVAC system comprises adjusting an operation of a heat exchanger. 
     
     
         15 . The method of  claim 11  wherein adjusting an operation of the HVAC system comprises adjusting an operation of an enthalpy wheel. 
     
     
         16 . The method of  claim 9  further comprising:
 determining a pressure level; and 
 adjusting an operation of the HVAC system based on the determined pressure level. 
 
     
     
         17 . An HVAC system for providing conditioned air to a space, comprising:
 a cabinet comprising;
 an inlet for an ambient airstream; 
 a supply airstream; 
 a return airstream; and 
 at least one heat exchanger; 
   a supply air temperature sensor;   a space temperature sensor;   a microprocessor coupled to the cabinet, supply air temperature sensor, and the space temperature sensor and operable to determine an ambient temperature based at least partly on a determined supply air temperature and a determined space temperature, the microprocessor configured to receive a temperature request, wherein when the request is to heat the space when the determined ambient temperature is greater than the determined space temperature or to cool the space when the determined ambient temperature is less than the determined space temperature, the microprocessor is configured to;
 restrict operation of a compressor within the HVAC system; 
 allow an ambient air to comprise a supply air of the HVAC system; 
 determine a change in the supply air temperature; 
 determine a change in the space temperature; and 
 adjust an operation of the HVAC system based on at least the determined change in the supply air temperature and the determined change in the space temperature. 
   
     
     
         18 . The HVAC system of  claim 17  further comprising a humidity sensor, and wherein the thermostat is configured to adjust an operation of the HVAC system based on at least the determined humidity level. 
     
     
         19 . The HVAC system of  claim 17  further comprising a pressure sensor, and wherein the thermostat is configured to adjust an operation of the HVAC system based on the determined pressure level. 
     
     
         20 . The HVAC system of  claim 17  further comprising a heat exchanger temperature sensor and a cabinet temperature sensor, wherein the thermostat is configured to adjust an operation of the HVAC system based on at least one of the heat exchanger temperature and the cabinet temperature.