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Sustainable Energy

  • Y. H. Venus LunEmail author
  • S. L. Dennis Tung
Chapter
First Online:
Part of the Green Energy and Technology book series (GREEN)

Abstract

There are many factors to study in designing sustainable heat pump systems. Among them, the loading calculation dictates the system’s equipment selection. Calculating the loading demand for equipment sizing and selecting high-performance system are important in the process to plan for sustainable energy system. When sizing a heat pump, it is essential to determine the required cooling and heating capacity. To begin, this chapter examines factors affecting the heating/cooling demand for indoor thermal comfort. Key variables of thermal comfort are also discussed. To further investigate energy efficiency, coefficient of performance (COP) is examined. There are several methods that exist in determining COP. Equations and methods to determine COP are investigated. Examples of COP calculation on water-to-water heat pump and air-to-water heat pump are illustrated. The findings indicate that the COP level varies with types of heat pumps.

Keywords

Load calculation Thermal comfort Balance point temperature Heating capacity Cooling capacity Coefficient of performance 

Nomenclature

Seasonal energy efficiency ratio

SEER

Seasonal energy efficiency ratio

Q

Reference annual cooling demand

QE

Annual electricity consumption

Subscript

c

Cooling

h

Heating

Nomenclature: Fanger’s comfort equation

Ici

Thermal resistance of clothing

M

Rate of metabolic rate production

Pw

Water vapor pressure

tmrt

Mean radiant temperature

ta

Air temperature

Va

Relative air velocity

Nomenclature: Heating and Cooling Capacity

Cp

Specific heat at constant pressure, expressed in joules per kilogram and kelvin

Ebal

Energy balance

Ein

Energy into a system

Eout

Energy out of a system

\(\dot{m}\)

Mass flow rate

QC

Cooling capacity, expressed in watts

QH

Heating capacity, expressed in watts

QHR

Heat recovery capacity, express in watts

q

Volume flow rate, expressed in cubic meters per second

r

Density, expressed in kilograms per cubic meter

∆t

Difference between inlet and outlet temperatures

Nomenclature: Coefficient of Performance (COP)

COPC

COP of cooling

COPH

COP of heating

COPHC

COP of heating and cooling

Qcd

Capacity of condenser (for heating)

Qev

Capacity of evaporator (for cooling)

Qhrc

Capacity of heat recovery of condenser (for heating)

Winput

Total input power

h1

Enthalpy in front of the compressor

h2

Enthalpy behind the compressor

h3

Enthalpy at the injection valve

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Copyright information

© Springer Nature Switzerland AG 2020

Authors and Affiliations

  1. 1.Sustainable Energy LimitedHong KongPR China
  2. 2.Sustainable Energy LimitedHong KongPR China

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