Self-test system for qualifying refrigeration chiller system performance
A chiller or cooler is disclosed, including a self-test mechanism to simulate a sampling of normal operations and to compare the operating parameters resulting from such sampling against factory operational parameters adjusted for differences in operating parameters so as to eliminate unnecessary servicing or maintenance events.
1. A chiller including a compressor, a condenser, a pump, an evaporator and a fan, the chiller providing a fluid at a selectable set point of temperature, the chiller having an integrated self-testing system comprising:
a) an air temperature sensor;
b) a fluid temperature sensor;
c) a controller, the controller generating in response to a user selection a first pretest signal for turning the fan on, the compressor off and the pump off, the controller connected to the air temperature sensor to measure the ambient air temperature resulting from the first pretest signal, the controller further generating a self test signal to the chiller to change the set point of temperature of the chiller a preselected amount, the controller further connected to the fluid temperature sensor to determine the self test cooling rate for the chiller to obtain the change in the set point, the controller further calculating an expected self test cooling rate using the ambient air temperature and a factory self test cooling rate stored in memory, and the controller further comparing the self test cooling rate and the expected self test cooling rate and generating a signal indicating whether the self test cooling rate and the expected self test cooling rate deviate by more than a preselected threshold;
d) a memory connected to the controller, the memory including preloaded factory self test cooling rate in response to factory implemented self test signals; and
e) an output interface connected to the controller for providing a signal indicating service requirement status in response to a controller input indicating that the self test cooling rate and the expected self test cooling rate deviate by more than a preselected threshold.
2. The chiller of claim 1 , wherein the signal provided by the output interface includes a graphical comparison of the self test cooling rate adjusted by the ambient air temperature versus the factory self test cooling rate.
3. The chiller of claim 1 , wherein the signal provided by the output interface includes at least one end user service recommendation.
4. The chiller of claim 3 , wherein the at least one end user diagnostic recommendation includes an automated adjustment of in situ operational parameters.
5. A method for self testing the efficacy of a chiller in situ, the chiller including a compressor, a condenser, a pump, an evaporator, a fan, a temperature sensor, and a fluid sensor, the chiller providing a fluid at a selectable set point of temperature, the method comprising the steps of:
a) storing a factory self-test cooling rate in a memory corresponding to the time required in factory to change the set point of temperature of the chiller a preselected amount;
b) sending a first control signal turning the fan on, the pump off, and the compressor off to determine the ambient temperature of the chiller;
c) sending a second control signal to the chiller to change the set point temperature a preselected amount and measure the time required to obtain the changed set point to determine the in situ self-test cooling rate;
d) adjusting the factory self-test cooling rate using the ambient temperature of the chiller to derive an expected self-test cooling rate; and
e) comparing the expected self-test cooling rate and the in situ factory self test cooling rate to provide a service requirement status output signal to a user when the in situ self test cooling rate and the expected self test cooling rate deviate by more than a preselected threshold.