OCTOBER 19-20, 2012 - YMCA University of Science & Technology

Proceedings of the National Conference on
Trends and Advances in Mechanical Engineering,
YMCA University of Science & Technology, Faridabad, Haryana, Oct 19-20, 2012
green house gases such as co2 and so2 . A study by American EPA has demonstrated that residential fossil fuel
heating system is in the USA produced anywhere from 1.2 to 36 times the environmental co2emissions from
15% to 77% could be avoided through the application of GHSP systems .
3. Experimentation
For a general steady state, steady flow process, the four balance equations, namely mass, energy, entropy and
energy balance equations are applied to ground source heat pump (GSHP) in ordered to find the heat input, the
rate of energy decreased, the energy and exergy efficiencies the mass and energy balance equations as well as the
exergy destruction obtained using the entropy and exergy balance equation for each of GSHP componets are
discussed in the following sections. Fig shows schematic diagram of GSHP considered for thermodynamic
analysis. The GSHP system consists of compressor, condenser, expansion valve, evaporator, fan-coil unit and
ground heat exchanger. It is assumed that the flow is steady through every component of the GSHP system heat
loss is ignored the governing equation for the individual components of the systems are derived as follows :
Compressor
Using the notation used to represents various stage points in GSHP system; the mass balance equation for
compressor can be expressed as
1 =2 = r
assuming no heat loss, using the energy balance equation the work input to the compressor can be expressed as
comp = r (h2-h1)
The exergy destruction, xdest,comp can be computed using exergy generation and energy balance equations .
Using these equation an expression for xdest,comp is given as follows
xdest,comp = r (Ψ1- Ψ2 ) + comp,act
Energy for any component can be found out using the formulas:
Exergy Ψ = (h-h0)-T0(s-s0)
Condenser
Mass balance for refrigerant flow in the condenser can be denoted as
2 = 3 = r
similarly the mass balance for air flow in the fan coil unit which is connected to the condenser for heat
extraction, can be expressed as
5 = 6 = w
the energy balance for refrigerant and air sides are given by
cond = r (h2-h3)
cond= fc= w =Cw (T5-T6)
The exergy destruction in the condenser is expressed as
Èxdest,cond =r(Ψ2- Ψ3)+ w(Ψ6- Ψ5)
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