The Oilon ChillHeat high-temperature heat pump can answer industry’s need for high temperatures
28 of April 2020
Heat pumps are a growing success story. By cooling a suitable heat source one can produce useful heat energy many times the amount compared to the energy taken up by the heat pump. In industry, the use of heat pumps is still in its infancy, but rapidly evolving technology is constantly opening new doors.
Industry generates a lot of waste heat that is vented to the open air or condensed into water. At the same time, fresh energy is paid for in the form of fuel, either heat or electricity. Energy demand and excess energy cannot normally be matched because the temperature levels are inappropriate.
Waste heat energy for processes
According to a recent preliminary study by Motiva (The Finnish state sustainable development company), Finnish industry produces about 16 terawatt hours (TWh) of surplus heat, which would be technically possible to utilise with existing technology. Much of the heat is lukewarm, about 50°C or less. Processes – and district heating, for example – often require temperatures in the range of +100°C.
The high-temperature technology of heat pumps developed in recent years is the answer to many needs. With Oilon high-temperature heat pumps it is now possible to capture energy from various cooling waters in the production process, or even from the washing water going to the sewer, and produce useful 100°C heat – and even hotter – for process use, wash water and heating.
Snellman is a pioneer user of heat pumps
Snellmanin Lihanjalostus Oy (Snellman Meat Refinement) in Pietarsaari is one of the first companies to use industrial heat pumps for waste heat recovery. Today industrial heat pumps from Oilon produce a remarkable share of heating energy at Snellman’s plant.
More than 10 years ago – before anybody actually even talked about industrial heat pumps – Markus Snellman, technical manager at the Snellman meat processing plant, discovered that a lot of energy was wasted with the hot water used for washing. A contact with Scancool that operated in Kokkola, next to Pietarsaari, and which was later acquired by Oilon, started the project in 2007.
Washing water uses a lot of energy
At a meat processing plant they use about one thousand cubic meters of hot water, every day. The temperature of the grey water flowing to Snellman’s own treatment plant is about +30°C, which gave an excellent starting point for the project.
Heating the water for washing takes about one megawatt (MW) of heating power and the warm water is needed 16 hours a day. The heat pump was designed according to this need for hot water. With the heat pump the temperature of the water was raised to +55°C and the result was a saving of approximately 450,000kg of heating oil per year; a semi-trailer load each month.
More pumps and higher temperatures
The next big step was taken in 2009. There are a huge number of cooling machines at the plant and Snellman realised that the condensing heat was being wasted.
“I asked Scancool if it would be possible to produce 75-degree temperature with a heat pump,” continues Snellman. “‘Yes, it should be okay,’ was the answer. With this energy we were able to heat the building and the whole process. Butchery, blanching machine and the whole production uses a lot of heat, about +60°C water.”
The latest step is two Oilon ChillHeat industrial heat pumps installed in January 2019, producing a temperature of +95°C. It is used, for example, for sterilising knives and other tools which requires a temperature of at least +82°C. The heat is also used for drying spaces after washing.
A heat pump saves the environment and money
High temperatures at the plant had previously been produced with steam from a biogas boiler. The Snellman meat processing plant moved to using biogas in 2014, replacing an oil-based system. Steam from the biogas boiler is now used much less, mainly for cooking sausages and hams.
“It is easy to work with Oilon,” says Snellman. “When I ask if they can do this or that, the answer is: ‘yes, surely’. When I ask if they can do +95°C, I hear: ‘certainly’. I will soon ask the next question: when do we get +150°C? I believe it is not very far away. Then we will no longer need the steam boiler.”
“When we install a heat pump we save the environment and also money. Last year we saved 580,000 €. And we save it every year! Heat pumps produce thermal energy four times the amount compared to consumed energy. Investment in a heat pump pays itself back in almost one year so it is difficult not to buy.”
Good use of waste heat at a plastic factory
Oilon has supplied Jackon Finland with an Oilon ChillHeat high-temperature heat pump, which produces a temperature of almost 100 degrees for the production process at the expanded plastic foam factory. The heat source used is the 50-60 degrees of waste heat from the process. This significantly reduces the carbon footprint of production.
The Jackon Finland Muurla plant manufactures expanded plastic foam products that are made by expanding in a mould. The expansion, or sintering, takes place with saturated steam at a temperature of about 120-140°C. Sintering steam is produced in a liquefied petroleum gas (LPG) heated boiler.
The sintering cycle takes 1-2 minutes, after which the mould is cooled down to about 90°C. The cooling of the moulds produces 50-60°C water, which is traditionally cooled to 30-40°C in a cooling tower. Waste heat was produced 3,000 megawatt hours (MWh) of energy per year.
In the factory’s production process heat is required in four heat treatment ovens in which products are placed to stabilise after sintering. About 95 degrees water is used to heat the ovens. High temperature – almost 100°C – is also needed in the impregnation of the raw material.
Lots of power with good efficiency
“We have previously used waste heat as extensively as possible for heating the property and all other heating targets,” says Jukka Mälkönen, production manager at the Muurla facility. “The temperature of almost one hundred degrees required for post-processing furnaces could not, how ever, be produced from waste heat. Previously, heat pumps could not produce a sufficiently high temperature.”
The Oilon ChillHeat P150 heat pump delivered to Jackon has a total rated heating power output of 372 kW and a COP (coefficient of performance) of 3.2, despite producing almost 100°C water. The two compressors of the heat pump are inverter controlled, providing excellent efficiency and a very wide capacity control range.
Towards ever higher temperatures
“Industrial heat pumps are not yet used for producing process steam, and the biggest and most economically profitable potential in industry at the moment is to produce temperatures close to 100 degrees,” says Martti Kukkola, chief business officer for industrial heat pumps and chillers at Oilon.
However, Oilon also manufactures pumps that produce heat above +100°C. The current delivery to Sweden produces +105°C heat for drying the aluminium powder. The system consists of two inverter-controlled Oilon ChillHeat P300s and one Oilon ChillHeat S180 industrial heat pump.
Their heat source is process cooling, where the inlet water temperature is +25°C. On the heating side, the inlet water is +96°C and the outlet a maximum +120°C. The thermal power of the system is 500 kW and COPh 2.2. Considering cooling, the overall efficiency is 3.4.
Designer needs good tools
Design is becoming increasingly complicated, product options are numerous and each project is unique. The designer needs to easily and quickly get information about equipment that is as accurate as possible.
Oilon has developed the Oilon Selection Tool program for designers to help them choose the right pump model for each situation. We had the opportunity to talk to Jussi Alilehto, senior consultant at Sweco, and hear his views on the needs and wishes of the designer.
“There are always countless things to consider when designing energy systems,” says Alilehto. “Heat pumps are complex devices and, at the design stage, one needs to get as accurate information as possible as to how they can be applied to different situations.”
“When designing, it is important to see all the details of the device – electrical features, flow and everything else. Mere kilowatt details do not tell you anything. There can never be too much information.”
“An important feature of the selection tool is also the ability to make versatile configurations, for example, multiple pumps in parallel or in series. The freely model-able options make it easy to optimise efficiency and temperature levels.”
The role of heat pumps will increase in the future
According to Alilehto it is obvious that the use of heat pumps will increase significantly from the current level. The plan to reduce electricity tax is one suitable step towards electrifying society and reducing burning. “Electricity is poison” is a weird old attitude. Heat pumps and wind power are steps towards an emission-free future.