The Oilon high-​temperature heat pump makes good use of the waste heat and reduces carbon foot­print at Jackon’s expanded plastic foam factory

Waste heat is often gen­er­ated in indus­try. The tem­per­a­tures required by the process at Jackon’s Muurla plant are very high, but the high-​temperature tech­nol­ogy of Oilon’s indus­trial heat pumps can match these demands.

Jackon Group is the leading insu­la­tion man­u­fac­turer in the Nordic coun­tries. At the end of last year, Ther­miSol, Tupler, Epsira and Pohjo­is­mainen Solu­muovi were merged into Jackon Finland Oy, part of the Nor­we­gian family-​owned Jackon Group. The Group pro­duces energy-​efficient solu­tions for con­struc­tion and indus­try, with a broad range of EPS, XPS and EPP insu­la­tors, pack­ages and com­po­nents.

Energy effi­ciency has been studied for a long time

The Muurla plant was prac­ti­cally rebuilt in early 2009, fol­low­ing a dev­as­tat­ing fire on Finnish Inde­pen­dence Day, Decem­ber 6, 2008.

All the firm’s dif­fer­ent expanded plastic foam prod­ucts – with the excep­tion of insu­la­tion boards – are made by expan­sion in a mould. Poly­styrene (EPS), poly­eth­yl­ene (EPE) and, increas­ingly, polypropy­lene (EPP) are used as raw mate­ri­als. The expan­sion, or sin­ter­ing, takes place with sat­u­rated steam at a tem­per­a­ture of about 120°C for poly­styrene and about 140°C for polypropy­lene.

The sin­ter­ing takes place in 20 large “fur­naces”. The expan­sion cycle takes just 1-2 minutes, after which the mould is cooled down to about 90°C. The process con­sumes a lot of energy. In addi­tion heat is required in four heat treat­ment ovens in which EPE and EPP prod­ucts are placed to sta­bilise after sin­ter­ing. EPS does not need this post pro­cess­ing.

“Ten years ago, we started research­ing for more effi­cient use of energy,” says Jukka Mälkönen, pro­duc­tion manager at the Muurla facil­ity. “The cooling of the moulds pro­duces 50-60°C water, which is tra­di­tion­ally cooled to 30-40°C in a cooling tower. It con­sumed 3,000 megawatt hours (MWh) of energy per year for small birds.”

“Even then we used the extra heat to the fullest extent, but for example, we were not able to produce the high tem­per­a­ture – almost 100°C – needed for the heat treat­ment ovens. Heat pumps at that time were not able to produce those tem­per­a­tures.”

Plan­ning required a lot of cal­cu­la­tion skills

Some years later Mälkönen read an article accord­ing to which heat pumps had reached tem­per­a­tures above 100°C. He con­tacted con­sul­tants in the field and met a few, but they were not offer­ing Oilon’s tech­nol­ogy. They offered com­plete solu­tions, but the prices of their pro­pos­als seemed very high.

“There was a lot of cal­cu­la­tion in the system design, but we knew best because we knew the process exactly,” Mälkönen con­tin­ues. “We pre­vi­ously had a strong rela­tion­ship with Oilon because we used their burners, for example, in the steam boiler. We started to design the whole system with them, because they have long expe­ri­ence of high-​temperature heat pumps and know-​how to make the cal­cu­la­tions.”

“We decided to make the nec­es­sary heat exchang­ers and assem­ble the system our­selves. Oilon helped us with the design and sizing of various details and pro­vided the suit­able heat pump for the purpose.”

Several high-​temperature heat streams

The cooling water from the moulds is fed into a 20m3 tank that has a tem­per­a­ture of around 50-60°C. The heat pump uses this cooling cycle as a source of heat, cooling the water to 40°C, while reduc­ing the need to use cooling towers.

The heat pump pro­duces about 95°C water, which is used to heat the after-​treatment ovens and premises. This replaces the use of steam and elec­tric­ity. On the other hand, the heat pump is also used for heating the boiler feed water.

Sin­ter­ing steam is still pro­duced at the factory in a liq­ue­fied petro­leum gas (LPG) heated boiler. Steam boiler feed water comes from the munic­i­pal water mains with an inlet tem­per­a­ture of 6-7°C and is heated to about 60°C by direct heat recov­ery. The heat pump further heats the boiler feed water up to about 80°C.

High tem­per­a­ture – almost 100°C – is also needed in the impreg­na­tion of the raw mate­r­ial and more than enough energy is also avail­able to heat the premises. All in all, the thermal energy avail­able is more than required by the facil­ity. Some of the heat goes to the cooling tower since, for example, the munic­i­pal­ity is not inter­ested in using it for dis­trict heating in Muurla village.

Lots of power with good effi­ciency

 “We ended up with the Oilon Chill­Heat P 150 heat pump,” says Martti Kukkola, Chief Busi­ness Officer, Indus­trial heat pumps and chillers at Oilon. “It is the right size for this system and it reaches very high tem­per­a­tures. The two com­pres­sors of the heat pump are inverter con­trolled, pro­vid­ing excel­lent effi­ciency and a very wide capac­ity control range.”

 “Jackon has a lot of waste heat at 50-60°C. However, the required process tem­per­a­tures are so high that it would not be pos­si­ble to use the waste heat with a con­ven­tional heat pump. Con­ven­tional heat pumps have yields in the range of 50-60°C, which is only the start­ing point for the require­ments here.”

Kukkola exten­sively praises the exper­tise of Mälkönen and his staff in, for example, demand­ing imple­men­ta­tion of crit­i­cal tube and shell heat exchang­ers. “The client built the system by them­selves. They have a lot of exper­tise.”

The Chill­Heat P150 heat pump deliv­ered to Jackon has a total rated heating power output of 372kW and a COP (coef­fi­cient of per­for­mance) of 3.2, despite pro­duc­ing almost 100°C water.

The heat pump refrig­er­ant (or heat trans­fer medium) is R1234ze. It is a new gen­er­a­tion refrig­er­ant which, together with the P-​Series heat pump, is capable of pro­duc­ing a tem­per­a­ture of 100°C. The sub­stance has a very low global warming poten­tial (GWP) of less than 1. The refrig­er­ant is A2L clas­si­fied, i.e. non-​toxic but slightly flam­ma­ble. Because of this, the heat pump is fully enclosed and equipped with a gas leak sensor and ven­ti­la­tion.

The heat pump is con­nected with remote con­nec­tion to the Oilon Global Monitor control system, which mon­i­tors equip­ment per­for­mance, usage rate, power gen­er­a­tion, and imme­di­ately reports any pos­si­ble abnor­mal oper­a­tion.

Afford­able and func­tional package

 “The heat pump was taken into oper­a­tion in early 2019 and we now have 11 months of sta­tis­tics on its oper­a­tion,” Mälkönen con­tin­ues in the inter­view con­ducted in January 2020. “During this time, the heat pump pro­duced 413MWh of heat and also sig­nif­i­cantly reduced the carbon foot­print of pro­duc­tion. Much more could have been pro­duced, but we had no place where to utilize it. The heat treat­ment fur­naces were under-​utilized last year, but this year all four will be fully oper­a­tional. On the other hand the heating of the prop­erty was only con­nected to the system in the spring.”

“Oilon’s strength is that they know how to cal­cu­late, so we got an exactly dimen­sioned solu­tion and, on the other hand, they also take care of the machine main­te­nance. Along­side this, our own exper­tise in imple­men­ta­tion made it pos­si­ble to put in the system at a rel­a­tively low cost. The heat pump accounted for a bit less than half of the total invest­ment, and we also received invest­ment support for our project. The payback period will be very rea­son­able.”

“The risks of the project were high when we started to apply this new tech­nol­ogy for a new purpose. However, every­thing has gone as we had hoped and there has been no trouble with the heat pump during the year. Every­thing has worked per­fectly. I am happy.”