The futuristic heat pump "the Ice-Stick" is efficient and environmentally friendly.

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Octopus Energy has developed and manufactured heat pumps since 1980. Its main objective has been to create heating systems that benefit our environment while keeping down costs.

1991 the company founder Kurt Karlsson develops, what makes Octopus Energi unique, the Ice-Stick (IS). This product is amazing with its simplicity, only very small adjustments were made since the manufacturing started. The Ice-Stick has heated many homes for almost 20 years and is very efficient and environmentally friendly.


1980 Kurt Karlsson developed a groundwater heat pump with an evaporator PEL tube and integrated capillary that was patented in seventeen countries. The evaporator construction made it possible to sub cool water and take 10W/l by freezing water to ice. The product is still manufactured and installed in houses and industries.

1982 Kurt Karlsson developed a tube heat exchanger, the construction was made of 600 m PEL tube and two evaporator PEL tubes. It became a combined air- and groundwater heat pump. Many installations are currently (2006-01-29) running.

1983 The Hässleholm model was an air-, drinking water heat pump installed in Hässleholm, the Community sold water to heat pumps.

Download pdf (Swedish) article 1, article 2

1987 The PEL tube evaporator was replaced by a direct expansion air fan evaporator with an automatic defroster, this made it easier to install.

1991 Kurt Karlsson develops the Ice-Stick, as a replacement for the air fan evaporator. Kurt had succeeded in making a heat pump as simple as a chest freezer. The effect was 48 times larger then a normal freezer.

The Ice-Stick consists of only one moving part the compressor, no pumps, no air fan, no losses in defrosting and no oil heater.

The Ice-Stick’s evaporator surface is enlarged 32 times compared to a normal 22 mm copper tube.

Download PDF (Swedish) article 3

1996 The manufacturing of the Ice-Stick is done by AB Lundgrens Mekaniska Verkstad.

Kurt Karlsson


1997 The OM400i is sold as a small district heating system with two water tubes connectable to the house heating system.The Ice-Stick is tested at the factory and Gasol (propane) is applied, could the heat pump technology become easier.

The OM400i is sold together with a new control system that divides the heat in the house and preheats the boiler water by taking advantage of the radiators and floor heating as a sun collector. To make this possible all thermostats have to be fully open the whole year.

1998 AB Lundgrens Mekaniska verkstad becomes a wholly owned subsidiary of Midway Holding AB. The Midway Holdings group is quoted on the stock exchange and is an industrial conglomerate with about 900 employees and a turnover about 2 billion SEK.

1999 Hundreds of OM400i combined with the new control system are operating. I some cases the ground water installation was replaced with an Ice-Stick, the energy saving was the same without the environmental disturbance.

2000 The manufacturing of the Ice-Stick is moved to Sösdala, in Octopus Energi´s own premises.

2004 The Ice-Stick is released in three new models, 48X, 61X and 81X. X is the number of chest freezers comparable to the size of the Ice-Stick. The breaking news is 61X, an Ice-Stick that can be combined with a 30-60 meter copper tube in the earth.

The combination makes it possible for the heat pump to use the earth when the temperature goes below minus Celsius, no pump is used the simplicity of the Ice-Stick is kept.

2006 The manufacturing is moved to Höör.

2009 The company becomes a member of the European heat pump association (

Kurt Karlsson

This is the story about a man with ideas long before his time. A man who’s creativeness and curiosity resulted in many exciting solutions.


Kurt Karlsson

Kurt Karlsson is still called the”Father of the Heat pump” by people from the old days. His early thoughts and ideas are still fundamental in the business today. Kurt’s ideas of saving energy are as topical today as they where in the sixties, when it was groundbreaking and largely unexplored territory.The story starts when Kurt left school after eight years and started selling freezers and refrigerators to stores. His thoughts began when he saw the waste of heat, in those days they just blew out the heat into the air outdoor, he asked himself “there most by an easier way to recycle the lost energy and at the same time lower the cost of heating the store?” Certainly this could be done, thus the adventures of Kurt Karlsson began.



1967 the company Kryotherm is formed in Furulund, Sweden, with a clear business concept ”Simplicity and low maintenance”. At Kryotherm Kurt developed a fundamental idea of recycling the surplus of heat. After some years Kurt left to pursue his new ideas. Today the company is operating in Finland, Norway and England with its head quarters in Piteå, Sweden.Kurt formed his second company Klimatkyla AB, it made big heat pump installations to industry and warehouse for example IKEA in Köping, Copenhagen and Oslo. In the seventies Euroc Development AB bought Klimatkyla AB and changed the name to Technoterm. Kurt was a part of the deal and was employed as an inventor within Euroc Development AB. During his time at Euroc he worked with for example sun collectors, heat pump technology combined with the sterling engine and making electricity from manure.
After a while at Euroc Kurt leaves to pursue his new ideas once again, this is the beginning of Octopus Energi AB. The name octopus is taken as it best illustrates the many ways of catching energy.

1980 Kurt further develops his thoughts, one of the results is a ground water heat pump with a PEL tube evaporator. This product is patented in seventeen countries. Today it is manufactured and sold by JMC Energi AB.

Two years later the precursor of the Ice-Stick is developed. It was a 600 meter long tube heat exchanger containing 200 liter 33 percent alcohol. Many of these heat pumps are still operating after 22 years (2006-01-28).

Some problems as bringing 200 liter alcohol solution at every installation and continually having to control the alcohol solutions protection from freezing where overcome by the developing of the air fan evaporator with direct expansion.

1991 the air fan evaporator is replaced by the Ice-Stick. The Ice-Stick didn’t need bought energy to defrost and the sound of the fan disappeared. In the Ice-Stick Freon was replaced with Gasol (propane), a more environmental useable gas.


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