Determining the coefficient of performance of a refrigeration system
First Claim
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1. A method for reducing the coefficient of performance to a design value from measured temperature conditions of a vapor compression type refrigeration system of the type having series arranged compressor, condenser and evaporator units and an electric motor for driving said compressor unit, said system further having a condenser water supply line and evaporator chilled water supply and return lines, said method comprising the steps of:
- storing a value (CWF) for the chilled water flow through said condenser;
sensing the condenser water supply temperature (Tcon),sensing the evaporator water supply and return temperatures (Tchw,in and Tchw,out),sensing the power input (φ
) to said motor;
calculating the cooling load (Qc)* from the expression Qc =CWF*(Tchw,in -Tchw,out);
storing the manufacturers'"'"' performance data for said system comprising the condenser supply water design (Tcon,D) and the evaporator return water design temperature (Tchw,D);
storing a value (α
temp) which is the ratio of the required change in condenser temperature to a unit change in chilled water temperature to maintain the same rated chiller capacity;
calculating the equivalent temperature (Tr) which compensates for variation from the given design temperatures from the expression
space="preserve" listing-type="equation">T.sub.r =(T.sub.con -T.sub.con,D)/α
.sub.temp -(T.sub.chw -T.sub.chw,D),storing experimentally determined coefficients b1, b2, and b3 for the quadratic expression
space="preserve" listing-type="equation">β
cap=b.sub.1 +b.sub.2 *T.sub.r +b.sub.3 *(T.sub.r).sup.2wherein β
cap is the ratio of the available capacity (CAP) at the actual chilled water and condenser water conditions to the design capacity (CAPD);
calculating said β
cap and said CAP;
calculating the part-load ratio Γ
load from the expression Γ
load =Qc /CAP, storing experimentally determined coefficients a1, a2 and a3 for the quadratic expression
space="preserve" listing-type="equation">δ
.sub.pow =a.sub.1 +a.sub.2 *Γ
.sub.load +a.sub.3 *(Γ
.sub.load).sup.2wherein δ
pow is a fraction of full-load power, calculating the full-load power (PFL) from the expression PFL=φ
*δ
pow ; and
calculating said COPA from the expression COPA=CAP/PFL.
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Abstract
The disclosure involves a coefficient-of-performance (COP) diagnostic method involving the use of novel algorithms for determining performance manifested faults of vapor compression type refrigeration systems.
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Citations
5 Claims
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1. A method for reducing the coefficient of performance to a design value from measured temperature conditions of a vapor compression type refrigeration system of the type having series arranged compressor, condenser and evaporator units and an electric motor for driving said compressor unit, said system further having a condenser water supply line and evaporator chilled water supply and return lines, said method comprising the steps of:
-
storing a value (CWF) for the chilled water flow through said condenser; sensing the condenser water supply temperature (Tcon), sensing the evaporator water supply and return temperatures (Tchw,in and Tchw,out), sensing the power input (φ
) to said motor;
calculating the cooling load (Qc)* from the expression Qc =CWF*(Tchw,in -Tchw,out);storing the manufacturers'"'"' performance data for said system comprising the condenser supply water design (Tcon,D) and the evaporator return water design temperature (Tchw,D); storing a value (α
temp) which is the ratio of the required change in condenser temperature to a unit change in chilled water temperature to maintain the same rated chiller capacity;calculating the equivalent temperature (Tr) which compensates for variation from the given design temperatures from the expression
space="preserve" listing-type="equation">T.sub.r =(T.sub.con -T.sub.con,D)/α
.sub.temp -(T.sub.chw -T.sub.chw,D),storing experimentally determined coefficients b1, b2, and b3 for the quadratic expression
space="preserve" listing-type="equation">β
cap=b.sub.1 +b.sub.2 *T.sub.r +b.sub.3 *(T.sub.r).sup.2wherein β
cap is the ratio of the available capacity (CAP) at the actual chilled water and condenser water conditions to the design capacity (CAPD);calculating said β
cap and said CAP;calculating the part-load ratio Γ
load from the expression Γ
load =Qc /CAP, storing experimentally determined coefficients a1, a2 and a3 for the quadratic expression
space="preserve" listing-type="equation">δ
.sub.pow =a.sub.1 +a.sub.2 *Γ
.sub.load +a.sub.3 *(Γ
.sub.load).sup.2wherein δ
pow is a fraction of full-load power, calculating the full-load power (PFL) from the expression PFL=φ
*δ
pow ; and
calculating said COPA from the expression COPA=CAP/PFL. - View Dependent Claims (2, 3, 4, 5)
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Current AssigneeHoneywell Incorporated (Honeywell International Inc.)
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Original AssigneeHoneywell Incorporated (Honeywell International Inc.)
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InventorsMathur, Anoop K.
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Primary Examiner(s)Tanner, Harry B.
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Application NumberUS07/089,712Time in Patent Office377 DaysField of Search62/125, 62/126, 62/127, 62/129, 165/11 R, 236/94, 364/551, 364/557, 364/506, 364/511, 374/39, 374/40, 374/41, 374/31, 73/112US Class Current62/127CPC Class CodesF25B 2500/19 Calculation of parametersF25B 49/02 for compression type machin...G01L 3/26 Devices for measuring effic...
