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Title: Device and method for measuring the coefficient of performance of a heat pump

Abstract

A method and instrument is provided which allows quick and accurate measurement of the coefficient of performance of an installed electrically powered heat pump including auxiliary resistance heaters. Temperature sensitive resistors are placed in the return and supply air ducts to measure the temperature increase of the air across the refrigerant and resistive heating elements of the system. The voltages across the resistors which are directly proportional to the respective duct temperatures are applied to the inputs of a differential amplifier so that its output voltage is proportional to the temperature difference across the unit. A voltage-to-frequency converter connected to the output of the differential amplifier converts the voltage signal to a proportional frequency signal. A digital watt meter is used to measure the power to the unit and produces a signal having a frequency proportional to the input power. A digital logic circuit ratios the temperature difference signal and the electric power input signal in a unique manner to produce a single number which is the coefficient of performance of the unit over the test interval. The digital logic and an in-situ calibration procedure enables the instrument to make these measurements in such a way that the ratio ofmore » heat flow/power input is obtained without computations. No specialized knowledge of thermodynamics or electronics is required to operate the instrument.« less

Inventors:
 [1];  [2]
  1. (Knoxville, TN)
  2. (Kingston, TN)
Issue Date:
Research Org.:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN
OSTI Identifier:
864889
Patent Number(s):
4432232
Assignee:
United States of America as represented by United States (Washington, DC) ORNL
DOE Contract Number:  
W-7405-ENG-26
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
device; method; measuring; coefficient; performance; heat; pump; instrument; provided; allows; quick; accurate; measurement; installed; electrically; powered; including; auxiliary; resistance; heaters; temperature; sensitive; resistors; placed; return; supply; air; ducts; measure; increase; refrigerant; resistive; heating; elements; voltages; directly; proportional; respective; duct; temperatures; applied; inputs; differential; amplifier; output; voltage; difference; unit; voltage-to-frequency; converter; connected; converts; signal; frequency; digital; watt; meter; power; produces; input; logic; circuit; ratios; electric; unique; manner; produce; single; interval; in-situ; calibration; procedure; enables; measurements; ratio; flow; obtained; computations; specialized; knowledge; thermodynamics; electronics; required; operate; voltage-to-frequency converter; temperature sensitive; difference signal; input power; resistive heating; electrically powered; temperature difference; heating elements; power input; differential amplifier; heat flow; output voltage; voltage signal; heating element; electric power; heat pump; input signal; digital logic; accurate measurement; directly proportional; frequency signal; logic circuit; pump including; calibration procedure; amplifier converts; air duct; situ calibration; in-situ calibration; frequency converter; unique manner; temperature increase; resistance heat; accurate measure; resistance heater; /73/62/374/

Citation Formats

Brantley, Vanston R., and Miller, Donald R. Device and method for measuring the coefficient of performance of a heat pump. United States: N. p., 1984. Web.
Brantley, Vanston R., & Miller, Donald R. Device and method for measuring the coefficient of performance of a heat pump. United States.
Brantley, Vanston R., and Miller, Donald R. Sun . "Device and method for measuring the coefficient of performance of a heat pump". United States. https://www.osti.gov/servlets/purl/864889.
@article{osti_864889,
title = {Device and method for measuring the coefficient of performance of a heat pump},
author = {Brantley, Vanston R. and Miller, Donald R.},
abstractNote = {A method and instrument is provided which allows quick and accurate measurement of the coefficient of performance of an installed electrically powered heat pump including auxiliary resistance heaters. Temperature sensitive resistors are placed in the return and supply air ducts to measure the temperature increase of the air across the refrigerant and resistive heating elements of the system. The voltages across the resistors which are directly proportional to the respective duct temperatures are applied to the inputs of a differential amplifier so that its output voltage is proportional to the temperature difference across the unit. A voltage-to-frequency converter connected to the output of the differential amplifier converts the voltage signal to a proportional frequency signal. A digital watt meter is used to measure the power to the unit and produces a signal having a frequency proportional to the input power. A digital logic circuit ratios the temperature difference signal and the electric power input signal in a unique manner to produce a single number which is the coefficient of performance of the unit over the test interval. The digital logic and an in-situ calibration procedure enables the instrument to make these measurements in such a way that the ratio of heat flow/power input is obtained without computations. No specialized knowledge of thermodynamics or electronics is required to operate the instrument.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1984},
month = {1}
}

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