System and apparatus for electronic control of an absorption refrigeration system

Abstract

This invention relates to a system and apparatus for electronic control of an absorption refrigeration machine. The flow of liquids within the machine, as well as the concentration of the refrigerant/absorbent mixture solution are precisely controlled through the use of solenoid valves. These solenoids are controlled via a microprocessor control system with various sensors attached, which may include fluid level sensors, pressure sensors, temperature sensors and other environmental data sensors.

1 . A refrigeration machine including:
 fluid operating devices; and   one or more pulse width modulated valves for controlling fluid flow between the fluid operating devices.   
     
     
         2 . The machine as claimed In  claim 1 , wherein the fluid operating devices include two or more of a condenser, an evaporator, a generator, an absorber, a fluid storage device, and one or more pre-chambers. 
     
     
         3 . The machine as claimed in  claim 1 , not requiring a fluid pump. 
     
     
         4 . The machine as claimed in  claim 1 , wherein one or more of the devices operate at high fluid pressure, and one or more of the devices operate at low fluid pressure. 
     
     
         5 . The machine as claimed in  claim 1 , wherein the devices include a generator, and a first pre-chamber for supplying fluid to the generator. 
     
     
         6 . The machine as claimed in  claim 5 , wherein the devices further include a second pre-chamber for supplying fluid to the first pre-chamber responsive to a deficient fluid level i the first pre-chamber. 
     
     
         7 . The machine as claimed in  claim 5 , further including a heater for heating fluid in the first pre-chamber. 
     
     
         8 . The machine as claimed in  claim 1 , wherein the devices include an absorber for receiving fluid from a generator via one of the PWM valves when a fluid level in the generator exceeds a predetermined threshold. 
     
     
         9 . The machine as claimed in  claim 1 , wherein the devices include a condenser for condensing fluid received from a generator, and for providing fluid to an evaporator via one of the PWM valves when a fluid level in the condenser exceeds a predetermined threshold. 
     
     
         10 . The machine as claimed in  claim 1 , wherein the devices include a fluid storage device to facilitate control of fluid concentration in the machine. 
     
     
         11 . The machine as claimed in  claim 10 , wherein a pulsed valve is located between the fluid storage device and an evaporator. 
     
     
         12 . The machine as claimed in  claim 1 , further including an absorber coupled to a pre-chamber via a unidirectional valve. 
     
     
         13 . The machine as claimed in  claim 1 , further including pressure and temperature sensors configured to determine fluid concentration. 
     
     
         14 . The machine as claimed in  claim 1 , wherein the fluid includes ammonia. 
     
     
         15 . The machine as claimed in  claim 14 , wherein concentration is determined using the equation:
     C =(−0.00012* T +0256)*( P +1)−0.003015* T+ 0 . 4515   
   Where:   P is the Relative pressure in Bar.   T is the temperature in degrees Centigrade   C is the ammonia concentration, being the ratio of the mass of ammonia in the solution to the total Mass of the solution.   
     
     
         16 . The machine as claimed in  claim 1 , further including a controller configured to control the pulsed PWM valves and therefore fluid flow between the fluid operating devices. 
     
     
         17 . The machine as claimed in  claim 1 , further including a back cooling apparatus for impeding overheating of the machine. 
     
     
         18 . The machine as claimed in  claim 1 , further including a hot water system for supplying hot water to a generator. 
     
     
         19 . The controller for controlling a refrigeration machine, the machine including fluid operating devices and one or more pulse width modulated (PWM) valves for controlling fluid flow between the fluid operating devices, the controller configured to:
 control one or more pulse or PWM signals to said valves.   
     
     
         20 . The refrigeration method including the step of:
 pulse width modulating (PWM) valves to control fluid flow between fluid operating devices.