Jackon’s plant, Muurla, Finland

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.”