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1 ENERGY PERFORMANCE ASSESSMENT OF HVAC SYSTEMS Purpose of the Performance Test: Estimate the energy consumption at actual load vis-a-vis design conditions. Performance Terms and Definitions TR The amount of cooling obtained by one ton of ice melting in one day: 3024 kCal/h 12,000 Btu/h 3.516 thermal kW. Performance Terms and Definitions Net Refrigerating Capacity Mass flow rate of the evaporator water multiplied by the difference in enthalpy of water entering and leaving the cooler, expressed in: kcal/h TR

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  • 1

    ENERGY PERFORMANCE ASSESSMENT OF HVAC SYSTEMS

    Purpose of the Performance Test:

    Estimate the energy consumption at actual load vis-a-vis design conditions.

    Performance Terms and Definitions

    TR

    The amount of cooling obtained by one ton of ice melting in one day:

    3024 kCal/h

    12,000 Btu/h

    3.516 thermal kW.

    Performance Terms and Definitions

    Net Refrigerating Capacity

    Mass flow rate of the evaporator water multiplied by the difference in enthalpy of water entering and leaving the cooler, expressed in:

    kcal/h

    TR

  • 2

    PPrreeppaarraattoorryy ffoorr MMeeaassuurreemmeennttss

    Test readings should be taken as nearly simultaneously.

    Performance Terms and Definitions

    kW/ton Rating

    Referred to as efficiency, but actually power input to compressor motor divided by tons of cooling produced (kW/ton). Lower kW/ton indicates higher efficiency.

    Performance Terms and Definitions

    COP

    Chiller efficiency measured in (cooling load) divided by input (electric power).

    Performance Terms and Definitions

    Energy Efficiency Ratio (EER):

    The higher the EER, the more efficient the unit.

    Smaller chillers Chiller's cooling capacity (in Btu/h) / Power input (in watts) The higher the EER, the more efficient the unit.

  • 3

    11--DDeetteerrmmiinnee tthhee nneett rreeffrriiggeerraattiioonn ccaappaacciittyy

    The accurate temperature measurement is very vital in refrigeration and air conditioning and least count should be at least one decimal.

    22-- MMeeaassuurreemmeenntt ooff ccoommpprreessssoorr ppoowweerr

    Power (kW) = 3 x V x I x cos

    33-- PPeerrffoorrmmaannccee ccaallccuullaattiioonnss

    The energy efficiency of a chiller is expressed in :

  • 4

    33-- PPeerrffoorrmmaannccee ccaallccuullaattiioonnss

    44-- PPeerrffoorrmmaannccee eevvaalluuaattiioonn ooff aaiirr ccoonnddiittiioonniinngg ssyysstteemmss

    MMeeaassuurreemmeennttss ttoo bbee RReeccoorrddeedd DDuurriinngg tthhee TTeesstt

    Evaporator a. Temperature of water entering evaporator b. Temperature of water leaving evaporator c. Chilled water flow rates d. Evaporator water pressure drop Compressor

    Compressor electrical power, kW