Objective
To meet the refrigeration requirements of the REBOUL factory in ANNECY and to optimise the use of the heat recovered to partially cover "static and dynamic" heating needs in the workshops and offices whilst at the same time obtaining the best possible levels of yield and operating costs.
Technical results :
The most important part of the installation is the heat pump built by QUIRI and we will confine our report to the pump as all the other components use conventional technology.
The study enabled the end user to discover his requirements and the potential performances of the plant.
A large number of malfunctions occurred with the Heat pump. These were not due to the process used but the technological environment.
As of now, solutions have not been discovered for three major drawbacks, viz :
- the electrical pressure equaliser which is difficult to adjust at low loads
- leaks of refrigerant which change the mixture ratios and require costly refills
- losses in mechanical efficiency from an as yet undetermined source.
Economic results :
Performance of the prototype heat pump.
Overestimation of refrigeration requirements and the oversizing of the heat pump, calculated for a summer running 16% higher than winter operation were the main reasons for fall-off in the prototypes yield and overall performances.
Analysis of the measurements implemented explain performance losses as follows :
- 10.6 % of loss was due to pressure and temperature conditions in the operation of the thermodynamic cycle,
- 12.1 % of loss was due to the inefiicient operation of the gas/liquid exchanger,
- 8.5 % of loss was due to radical overheating which caused a lower volumetric yield and affected the isentropic effort,
- 12.4 % of loss was due to low motor load yield;
- an incalculable % was due to partial load operation, implying :
* lower specific power
* degraded mechanical yield from the motor and particularly the compressor.
The following performances were measured in operating conditions often very different from normal :
- Specific production : 3 kWF/kWe (variation from 2.2 to 3.3)
- Theoretical COP : 4.4 to 4.5 (variation from 3.4 to 4.8)
- True COP : approximately 4
- Average refrigeration effect obtained :
* at 68% of the Winter running power rating
* at94% of the Summer running power rating
- Electrical power consumption : 105% of rated power consumption
- True electrical power : 285 kWF (variation from 170 kW to 317 kW)
1. The technology used :
The innovatory technique employed results from using a non-azeotropic refrigerant mixture in the refrigeration compressor to enable a COP of approximately 7 in the specified operating conditions. The use of this refrigerant (FRIMIP 120, developed by the French Petroleum Institute - IFP) implied specific modifications to the cooling circuit :
- Perfect counter-current coil type QUIRI evaporator-condenser heat exchanger.
- Installation of a refrigerant sub-cooling unit
- Specific mechanical design for the sealing system on the compressor suction manifold (conventional QUIRI CF 80 compressor).
2. Operating conditions observed since commissioning (approximately 12 months) :
- Oversized heat pump due to overestimation of requirements
- Industrial capacity far below foorecasts (COP of 4.4 instead of 7)
- Average and punctual performances : deviation can be explained and if the system were to operate at 100% capacity it appears likely that the predicted COP would be obtained.
3. Economic aspects :
The additional costs incurred for the installation, basically related to the studies undertaken and equipment development to the heat pump and the final figure is likely to reach approximately 800000 FF.
Costs would only be marginally reduced if exchangers were mass produced.
Topic(s)
Call for proposal
Data not availableFunding Scheme
DEM - Demonstration contractsCoordinator
69006 Lyon
France