Heat pumps are the future of energy efficiency

Lämpöpumput ovat ratkaisu tulevaisuuden energiatehokkuuteen

In the future, heat pumps will take care of space heating. This is an opinion shared by many industry specialists and voiced by Helen Oy’s CEO Juha-Pekka Weckström in a recent interview. Oilon has worked hard for nearly two decades to turn this vision into reality and now, the time is close at hand.

When talking about heat pumps, the image that often comes to mind is an air-to-air heat pump sticking out of the wall of a house. Another alternative is a ground source heat pump that extracts energy from a borehole to provide heating for a single-family home. This article won’t discuss either of these. Today’s topic is large industrial heat pumps and heat pump systems which provide heat for industrial processes and district heating or provide heating and cooling for large buildings and properties. These solutions have a central role in the Oilon Group strategy.

From something pieced together into an industrial product

The story begins in the 2000s with Scancool, a refrigeration contractor providing services for refrigeration plants. The people in the company noticed how much waste heat these plants produced and started developing technology for extracting and using this waste heat. This was something no one had really done before. Oilon had already seen where the energy industry was heading and had started the pioneering work for utilizing heat pumps. Large industrial-scale heat pumps quickly found their way into Oilon’s strategy, and soon, Scancool became part of the company.

Early on, only small numbers of heat pumps were made. Each unit was a “project machine” tailored to a specific purpose. The components were selected case-specifically, which meant that large-scale production wasn’t feasible. The upside for these projects was that they provided experience of different solutions and understanding of industrial processes, such as which temperatures could be utilized, the temperature levels required, and the variation in loads. This experience would serve as capital for the future.

Oilon has a long tradition in machinery manufacturing, and manufacturers want to make products, not individually tailored machines. Encouraged by their early experiences, Oilon started to invest heavily in product development, production quality, and productized solutions.

Before a product is launched for sale, it will undergo extensive testing that will ensure its operability and performance. If testing reveals a weak link such as an incorrectly sized component, the component will be replaced in the machine being tested and in all future machines of that model series. Only products ready for their intended purpose will be offered for sale. As there is no such thing as a perfect product, quality improvement is a continuous process which results in new and improved products.

Industrial heat pumps are a proven and accepted solution

“In recent years, industrial heat pump sales have grown rapidly,” says Martti Kukkola, Oilon’s chief business officer for heat pumps and chillers. “Recently, our annual sales figures have nearly doubled, and we have just quadrupled our production floorspace and capacity.” The company’s industrial heat pumps are produced in Kokkola, Finland. Exports account for two thirds of the sales.

“Our main markets are Northern Europe, Great Britain, and China. The Central and Eastern European markets are showing good growth, and we have gained good traction in South America, for example.”

According to Kukkola, Finnish customers play a key role in the company’s success. As an example he mentions an air-to-water heat pump system that is currently being built for Fortum. Once complete, the Vermo plant will produce district heating and cooling for the city of Espoo in Finland. With a capacity of 11 MW, it will be the largest of its kind in the country and will help Fortum replace some of its coal-based energy production. The project’s 1.3-megawatt pilot phase is already complete. “Oilon has long-standing co-operation with all significant energy companies in Finland,” Kukkola continues. “Right now, many companies stand to gain a lot from combined heating and cooling (CHC), which means using a single machine to produce both heating or cooling at the same time.” Traditionally, large buildings have been chilled with water chillers, and the waste heat has been simply dumped into the atmosphere. A CHC machine will not only provide cooling but also transfer the extracted heat to a district heating network or the building’s hot water system.

“All heat pumps give out heat in one place and cool down another area, this is just how heat pumps work. In CHC solutions, we simply put both the heating and cooling provided into good use. For Helen Oy, we have completed around 20 CHC projects and several are underway, just to give an example.”

Oilon offers an extensive range of industrial heat pumps

Oilon’s range of industrial heat pumps can be divided into three product groups based on their compressor technology. Each group consists of several machines with different capacities.

The Oilon ChillHeat RE product family utilizes scroll compressors. Each unit is equipped with 2–4 compressors, and the available capacity range is 100–1,000 kW. The units are especially suited for producing flow temperatures up to +65 °C from a cold, around 0 °C input stream.

The eight ChillHeat P series heat pump models have 1–6 piston compressors. The available capacity ranges from 30 to 1,000 kW. P series machines are set apart by their ability to reach extremely high temperature output levels, all the way up to +120 °C. The units have a good coefficient of performance even at partial load, and they offer a wide capacity range.

Similarly to the RE and P series units discussed earlier, the 100–1,000 kW ChillHeat S heat pumps are housed in an enclosure. The heat pump housing is never wider than 911 mm, allowing units to be brought in to their installation site through normal doorways.

In addition to these units that have a housing, the S series includes larger models all the way up to the 5 MW capacity range. S series heat pumps utilize screw compressors, and they are well suited for high-capacity applications with a maximum flow temperature of around +85 °C. These machines allow operators to utilize industrial waste heat on a large scale.

How big is big enough?

“It’s been wonderful to witness the increasing demand for high-capacity heat pump systems first hand,” Kukkola says. “Most of the projects we’ve reviewed have been in the 200-megawatt range. However, there was this 20-MW project in Germany where the request of quotation specified that each heat pump must have a capacity of at least 10 MW. It baffles my mind why the capacity of a single heat pump would matter.

“What does matter is the COP, maintenance costs, space requirements, partial capacity range, redundancy, delivery time, and contract price. When these factors are ranked, what difference does it make if the system has two or 20 heat pumps? In big projects, this is something we have to discuss time and again. Sadly, often the projects have been at such an advanced stage that the customer hasn’t dared to question the pump-specific capacity requirement.”

According to Kukkola, a large heat pump is not necessarily a more economical solution. As a large heat pump is always a specialty product, things like spare parts can be expensive. In either case, the customer will need to commit to a single supplier. A combination of smaller heat pumps will always have a wider capacity range than a single large one. The space requirements are typically not that different either, especially in terms of volume.

System expertise and extensive control capabilities

One of Oilon’s strengths in the heat pump business is the company’s knowledge of different systems. This gives Oilon the ability to connect several heat pumps, often of different types, into an economical and optimized system that operates at the required temperature level and with the required capacity. In some cases, the entire system has been built into an insulated container that can be delivered on site with a truck, enabling rapid turnkey installation.

The key to designing complex systems of several heat pumps – “trains” as they are referred to within the company – is Oilon Selection Tool (OST). The internally-developed software tool allows engineers to examine how different combinations of heat pump models operate when connected in series and in parallel. The tool allows engineers to simulate the system’s operation accurately with different settings: at different inlet and flow temperatures for the hot and cold side and at different load points. For example, an S series heat pump produces heat at a high capacity and a medium temperature. The temperature can be boosted by P series heat pumps, which provide higher temperatures and expand the system’s operating range.

Oilon ChillHeat heat pump systems can reach capacities of 50 MW or more. Regardless of the size, the customer needs to provide only a single inlet and outlet connection point; what lies between those points is a solution engineered by Oilon and built by the company with an Oilon-authorized installation partner.

For managing individual heat pumps and extensive heat pump systems, Oilon has developed the Oilon Global Monitoring (OGM) system. In this system, heat pumps are connected to a data network and send their operating data to the cloud. Users can quickly view information about potential problems, and engineers can utilize historical data for remote servicing.

Customers can create reports covering device utilization, energy output, and the cost savings generated.

Top three uses for industrial heat pumps

Based on Oilon’s experiences, there are three major applications for industrial heat pumps, each with slightly different requirements. The applications are heating and cooling for large buildings and properties, utilizing industrial waste heat and generating process heat, and producing district heating and cooling.

During summer months, large buildings require cooling. The recovered heat can be used to heat up the domestic hot water used in the building. In winter, the same system can be used to recover heat from the building’s exhaust air and return it to the building’s heating system. These applications don’t require especially high temperatures and the required capacity is usually in hundreds of kilowatts, which means that RE series heat pumps suit this purpose well. RE heat pumps can easily produce temperatures over +60 °C even from a cold inlet stream.

Industrial waste heat can be utilized effectively with S series heat pumps. If the application requires especially high flow temperatures, P series heat pumps can be used either alone or connected in series with S series models. In solutions where only one heat pump can be used, the heat pump must be able to operate at both high and very low loads. P series heat pumps have a wide capacity and temperature range, S series models operate in a narrower range.

Producing district heating and cooling with heat pumps is becoming increasingly popular. District heating typically needs a big “boost”, which means that a high increase in temperature is required. P series heat pumps fit the bill exactly, especially in small-scale plants. These types of projects tend to involve a CHC solution. In large-scale projects that require a lot of capacity, a combination of S series and P series heat pumps can be used.

Heat pumps and the future of energy efficiency

“Heat pumps are one of the best solutions for utilizing renewable energy in the future,” Kukkola says. “In Europe, building heating and cooling accounts for half of all energy consumed; in Finland, heating alone accounts for a quarter.” The lion’s share of this heating energy is produced using some type of combustion. To achieve carbon neutrality, we will need to substantially reduce combustion and utilize renewable energy sources.

Temperatures in renewable energy sources, such as the soil and air, tend to be low. With a heat pump, these low temperatures can be boosted economically to the relatively high level required by heating.

Additionally, heat pumps can be used to recycle energy. When a building needs cooling, heat is generated for use elsewhere. If there is any heat in wash water or sewage, the excess heat can be extracted and utilized. In industrial operations, the range of potential applications is massive.

“We’ve got to remember that electricity plays an ever-increasing role in our society,” Kukkola continues. “In many cases, electricity is the cheapest form of energy available, and heat pumps deliver many times over the energy they consume. It is easy and economical to store heat.

“Where we stand now is only the beginning! We’re about to enter a very busy and interesting decade – the decade of heat pumps.” Industrial heat pumps are central to the Oilon strategy, and the business is about to expand by an order of magnitude.