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
• U-Pipes in this two straight pipes are connected by a 180 turn at bottom
• Concentric (coaxial) pipes
3. THERMAL MODELING
Thermodynamic analysis of a GSHP system is carried out initially in order to understand the performance of
individual components of the system. For this purpose First law of thermodynamic for open system is utilized
to model the individual components. Then the energy flow analysis of each component is also studied in detailed
to estimate the overall performance of GSHP system. The detail of thermodynamic modeling and energy analysis
is discussed in the following section.
For a general steady-state, steady flow process, the four balance equation, namely mass, energy balance
equations are applied to ground source heat pump (GSHP) in order to find the heat input, the rate of mass of flow
of refrigerant flowing into the circuit. Figure 3 show the schematic diagram of the 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 and heat loss is ignored. The governing equation for the individual Component of the system are
derived as follow
The mass balance equation can be expressed in the rate form as
in= out ( 1 )
Where is the mass flow rate, and the subscript is stand for inlet and outlet.
in= out ( 2 )
Energy balance equation can also be written more explicitly as
Q + inh in = Ẁ + outh out ( 3 )
Where, Q = Q net.in = Q in – Q out is the rate of net heat input Ẁ = Ẁ net, out = Ẁ out - Ẁ in is tge rate of net work output
and h is the enthalpy per unit mass.
The rate form of the entropy balance can be expressed as
S in - S out + S gen =0………………………………………………(4)
3.1 Compressor
Figure 3. The Main Components and Schematic of the GSHP
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