Experimental Case Study - Design for Micro-Combined Cooling, Heating and Power Systems - page 371

Fig. 21 Thermal agent distributions in residence

Circuit of hot/cold water distribution to the residence (CH5/CH6)
The CH5 circuit has the role of distributing hot water to the residence (for
heating during winter), while the CH6 circuit

that of distributing cold water to the
residence (for cooling during summer). Commutation from hot/cold water supply is
through three-way control valve driven by electric motor. The thermal load of the
circuits is represented by a system of ventilo-convectors and heaters placed inside
the heated spaces. The source of heat or cold may be the hot water tank or the cold
water tank. The thermal agent is nonharsh, treated water, which is circulated in the
hydraulic circuit by a pump. This pump is placed on the return of the thermal agent
which comes from the ventilo-convectors or radiators. The circuit contains the
following: a pumping group, separation valves, one-way valves,

—

filter for impuri-
ties, and thermometer which indicates the temperature of the agent. The structure of
the circuit is presented in Fig. 21 .
Circuits of the cogeneration unit devoted for heat recuperation and protection
(CH7 and CH8)
The Stirling engine as cogeneration unit is capable of supplying part of the heat
with the hydraulic circuit CH7. The heat transfer from the Stirling engine is
achieved through the recirculation of the thermal agent with a recirculation pump
located inside the Stirling engine. When selecting care should be taken from the
outset to ensure the lowest possible

flow temperature (CHP outlet), because the

electrical ef ciency depends on the cooling water temperature. This should not

exceed 65 C. For this reason the system must automatically vent to the outside the

heat. The CH8 circuit has the role of rejecting the heat taken up from the CH7 and

°