Fan coil air conditioning system, a fan coil unit, and a method of controlling a fan coil air conditioning syst

Abstract

A fan coil air conditioning system comprises at least one fan coil unit, the fan coil unit comprising a heat exchanger, at least one fan, a return air inlet and a conditioned air outlet. The heat exchanger comprises a cooling water connection for connecting to a source of cooling water, and a heating water connection for connecting to a source of heating water. The cooling water connection and the heating water connection are each provided with a respective motorised regulating flow valve. The system further comprises a controller operative to receive an air temperature signal and fluid temperature signals, and also a duty signal indicative of the temperature and volume flow rate of the conditioned air required for the conditioned air outlet in question. The controller subsequently generates a valve control signal to control the motorised flow valves.

1 . A fan coil air conditioning system comprising at least one fan coil unit, the fan coil unit comprising a heat exchanger, at least one fan, a return air inlet and a conditioned air outlet for connection to a conditioned air delivery duct in a building, the heat exchanger comprising a cooling water connection for connecting to a source of cooling water, and a heating water connection for connecting to a source of heating water, the cooling water connection and the heating water connection each being provided with a respective motorised regulating flow valve, the fan being operative to draw air from the air inlet, through the heat exchanger to condition the temperature of the air, the temperature being determined by the flow of cooling or heating water through the heat exchanger, and to pump the conditioned air through the conditioned air outlet, the system further comprising an air temperature sensor operative to generate an air temperature signal indicative of the temperature of the air returning to the fan coil unit, and fluid temperature sensors operative to generate fluid temperature signals indicative of the temperature of the fluids at the heat exchanger, the system further comprising a controller operative to receive the air temperature signal and the fluid temperature signals, and also a duty signal indicative of the temperature and volume flow rate of the conditioned air required for the conditioned air outlet in question, the controller being operative to subsequently generate a valve control signal to control the motorised flow valves in dependence upon the fluid temperature, air temperature and duty signals such that the flow rate of cooling and/or heating fluid and the flow rate of air through the heat exchanger, match the conditioned air duty required. 
     
     
         2 . The fan coil air conditioning system of  claim 1  wherein a humidity sensor is provided operative to generate a signal indicative of the relative humidity of the air returning to the fan coil unit. 
     
     
         3 . The fan coil air conditioning system of  claim 1  wherein the air temperature sensor comprises a sensor at the air inlet operative to measure the temperature of the air returning to the fan coil unit from the building. 
     
     
         4 . The fan coil air conditioning system of  claim 1  wherein the air temperature sensor comprises a sensor at the conditioned air outlet operative to measure the temperature of the conditioned air leaving the fan coil unit to the building. 
     
     
         5 . The fan coil air conditioning system of  claim 1  wherein the fluid temperature sensors comprise sensors at the cooling water connection operative to measure the temperature of the cooling water flow to and return from the heat exchanger, and further comprise sensors at the heating water connection operative to measure the temperature of the heating water flow to and return from the heat exchanger. 
     
     
         6 . The fan coil air conditioning system of  claim 1  wherein the controller comprises a remote controller and a fan coil unit controller, the remote controller being operative to form a data connection with the or each fan coil unit controller. 
     
     
         7 . The fan coil air conditioning system of  claim 1  wherein the controller comprises a fan coil unit controller on the fan coil unit itself. 
     
     
         8 . The fan coil air conditioning system of  claim 1  comprising a plurality of fan coil units. 
     
     
         9 . The fan coil air conditioning system of  claim 8  wherein each fan coil unit is provided with a unique identification, a signal indicative of the identification being provided to the controller. 
     
     
         10 . A fan coil unit comprising a heat exchanger, at least one fan, a return air inlet and a conditioned air outlet for connection to a conditioned air delivery duct in a building, the heat exchanger comprising a cooling water connection for connecting to a source of cooling water, and a heating water connection for connecting to a source of heating water, the cooling water connection and the heating water connection each being provided with a respective motorised regulating flow valve, the fan being operative to draw air from the air inlet, through the heat exchanger to condition the temperature of the air, the temperature being determined by the flow of cooling or heating water through the heat exchanger, and to pump the conditioned air through the conditioned air outlet, the fan coil unit further comprising an air temperature sensor operative to generate an air temperature signal indicative of the temperature of the air returning to the fan coil unit, and fluid temperature sensors operative to generate fluid temperature signals indicative of the temperatures of the water at the heat exchanger, the fan coil unit further comprising a fan coil controller operative to receive the air temperature signal and the fluid temperature signal, and also a duty signal indicative of the temperature and volume flow rate of the conditioned air required for the conditioned air outlet in question, the controller being operative to subsequently generate a valve control signal to control the motorised flow valves in dependence upon the fluid temperature, air temperature and duty signals such that the flow rate of cooling and/or heating fluid and the flow rate of air through the heat exchanger, match the conditioned air duty required. 
     
     
         11 . The fan coil unit of  claim 10  wherein a humidity sensor is provided operative to generate a signal indicative of the relative humidity of the air returning to the fan coil unit. 
     
     
         12 . An electronic controller arranged to control the fan coil air-conditioning system of  claim 1 . 
     
     
         13 . A method of controlling a fan coil air conditioning system comprising at least one fan coil unit, the fan coil unit comprising a heat exchanger, at least one fan, a return air inlet and a conditioned air outlet for connection to a conditioned air delivery duct in a building, the heat exchanger comprising a cooling water connection for connecting to a source of cooling water, and a heating water connection for connecting to a source of heating water, the cooling water connection and the heating water connection each being provided with a respective motorised regulating flow valve, the fan being operative to draw air from the air inlet, through the heat exchanger to condition the temperature of the air, the temperature being determined by the flow of cooling or heating water through the heat exchanger, and to pump the conditioned air through the conditioned air outlet, the system further comprising an air temperature sensor operative to generate an air temperature signal indicative of the temperature of the returning to the fan coil unit, and fluid temperature sensors operative to generate fluid temperature signals indicative of the temperature of the fluids at the heat exchanger, the system further comprising a controller, the method comprising steps of using the controller:
 to receive the air temperature signal and the fluid temperature signals, and also a duty signal indicative of the temperature and volume flow rate of the conditioned air required for the conditioned air outlet in question, and to subsequently generate a valve control signal to control the motorised flow valves in dependence upon the fluid temperature, air temperature and duty signals such that the flow rate of cooling and/or heating fluid and the flow rate of air through the heat exchanger, match the conditioned air duty required.   
     
     
         14 . The method of  claim 13  comprising steps of providing a humidity sensor, and generating a signal indicative of the relative humidity of the air returning to the fan coil unit.