Nortura, Tønsberg recovers waste energy from screw compressors
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Single stage heat pump at Nortura Rudshoegda, Norway
A single stage heat pump of 650 kW is installed at Nortura Rudshoegda in Norway. They have a large need of hot water at 83°C that is now produced by the hybrid heat pump.They had from earlier installed two low-temperature heat pumps that preheat water to a temperature of 50°C ammonia heat pump utilising ammonia gas from the condensers. The hybrid heat pump upgrade the energy in the 50°C of the water to a higher temperature. The hybrid heat pump heates a secondary circuit of process water to 86-87°C.
A larger picture of the prosess here
The installation was finalized in June 2007 and put into operation during the sommer. The heat pump saves 3,4 GWh each year and reduces the CO2-emmision with 850 tons every year. COP for this installation is about 5,3. The project has a pay-back at about 2 years.
The 650 kW hybrid heat pump at Nortura, Rudshøgda
Two stage hybrid heat pump at TINE Naerboe, Norway
At the dairy waste heat of 50°C (daytime) and 35°C (nighttime) is used as heat source to deliver heat up to 85 - 95 °C depending of the needs in the processes. Some of the heat is delivered to a district heating system. The heat pump also produces cooling water of 10 – 15 °C, which is used to cooling of several machines.
The heat pump process at Naerboe
The heat pump has more than 40 000 hours of running. The installation was fulfilled in 2003, and the pay-back time was less than two years. Maintenance check was done after 20 000 hours of running and the piston, piston rings and valves were only worn about 20-30% of the service limit and left running for more hours. The heat pump delivers 300-350 kW of hot water and about 220 kW of cooling water. COP for the installation is 2.7 – 3.0, but the total average COP for both heating and cooling is around 4.5.
For some markets there are several advantages with the hybrid heat pump compared to for instance vapour compression cycle with ammonia as working fluid:
- Waste heat recovery to deliver high temperatures (up to 130 °C depending on the heat source)
- High flexibility of temperature glide and lift because of two extra control mechanism
- Change of circulation ratio (Changes temperature glide)
- Liquid level setpoint (Changes temperature levels and duty)
- Suitable for work with high temperature lift from lower to upper temperature (Two stage system)
- Natural working fluid (water and ammonia)
- Good COP at high temperature lift and temperature glide
- Use of standard "low pressure", well tested components for ammonia refrigeration systems to keep cost low and reduce risk of failure
Heat Recovery Analysis
Every company whishes to have low energy costs. Even an initial optimal process has often been changed many times during the years and may not work optimally anymore. A practical heat recovery analysis will help to evaluate this.A heat recovery analysis fram Hybrid Energy AS will examine the most important process streams in the company. The need for heating and cooling is decided and which kind of utility systems is already in use. The minimum use of energy is established. The potential energy saving is found, both theoretically and practically.
The heat recovery analysis will evaluate heat recovery by use of direct heat exchange and several heat pumps solutions. In addition to known energy efficiency systems the use of the hybrid heat pump is evaluated by Hybrid Energy AS. This may be a very energy saving and economically favorably solution.
