Presentation Title Date xx, 2004

1
GROUND SOURCE HEAT PUMP AT HIREF FACTORY
(ITALY) Mauro Mantovan, Fabio Faro, Rossano
Lazzarin, Fabio Poletto, Andrea Quercioli, HiRef
S.p.A. Giacomo Benassi, Davide Del Col,
University of Padova
Building and Use
Heating Cooling System
Heat Pump

• Optimization strategy for electricity consumption
  Summer mode
• desired hygrothermal conditions 25 C _at_ R.U.
  55
• dynamic analysis of the thermal load of the
  building provides the energy distribution versus
  the thermal power
• Controls
• Geothermal probes a proportional-integral
  control is used for the condensing pressure by
  varying the water flow
• Cooling capacity a proportional-integral
  control is used for the water tank (90 L)
  temperature by varying the speed of the
  compressor
• User circuit the air flow in the fan coil and
  the water flow in the hydronic circuit are
  controlled to maximize the evaporation
  temperature and minimize the electric absorption
  of compressor user pump fan coil

• Characteristics of the heat pump
• nominal performance in cooling mode
• 14.0 kW _at_ 12 / 6.9 C 25.1 / 30.3 C
• nominal performance in heating mode
• 14.1 kW _at_ 40.3 / 45.0 C 14.1 / 9.2 C
• refrigerant R410A
• scroll compressor with asynchronous el. motor
  driven by inverter
• polyvalent heat pump 3 heat exchangers to
  operate in cooling/heating mode and for DHW
  production
• 4 ways valve on user and probes side of hydronic
  circuit to work always with countercurrent flows
  
• electronic expansion valve
• inverter pumps on user pipes circuit,
  constant velocity on DHW side
• acquisition system for electricity consumption,
  thermal power/energy supplied and dissipated,
  parameters of the refrigerant circuit and
  geothermal heat exchangers .

• The thermal system installed provides
• technical offices cooling demand in summer
• peak of 14.0 kW
• latent sensible
• technical offices heating demand in winter
• peak of 13.2 kW
• domestic hot water demand for the factory .

Sensible latent load _at_ 8C inlet water
temperature
Borehole Heat Exchanger

• Four - in parallel - BHEs with bentonite filling
• 140 mm borehole diameter deep 80 m
• two double U BHEs
• in. Diameter 26.6 mm
• Thickness 2.9 mm
• two single U BHEs
• in. Diameter 32.6 mm
• Thickness 3.7 mm
• Thermal response test on BHEs
• Infinite line source model analysis

• a proportional-integral control provides a PI
  signal based on the deviation of the hygrothermal
  conditions from setpoint .

Experimental measurements
Hydronic Circuit
Dynamic of the step response of the compressor
Fancoil Galletti mod. Flat

• the fan is driven by a brushless electric motor
  driven by inverter
• a microprocessor is installed with Modbus serial
  communication it allows the remote control
  (open/close the valve, vary the speed of the fan,
  read the temperature and humidity of the incoming
  air measured on board ).