A common reproach of Eco Cute is their difficulty in performing in cold climates. A solution to this problem has been proposed in form of a hybrid system, giving the CO2 hot water heat pump support from electric heaters when temperatures drop. A school canteen in the northeast of Japan that was equipped with the system two years ago shares its experience.
The central school canteen in the city of Ninohe in the prefecture of Iwate in the northeast of Japan was looking for a system that would deliver daily large amounts of hot water in a fairly cold climate. The choice fell on a hybrid system combining Eco Cute – Japanese R744 heat pumps - and heaters.
Five years ago the two cities of Ninohe and Jouhouji grew together to form one large agglomeration. As their school canteens which deliver the food to 14 primary and junior high schools in the neighbourhood were obsolete, they decided to build a new central school canteen, state-of-the-art in hygiene management. The new central school canteen was finished in 2009 to produce and deliver around 2,800 meals per day. In the refurbishment of the canteen it was decided to opt for an all-electric system and to test a heat pump system for the hot water supply. The canteen has a very high hot water demand, especially in the afternoon between 2-3 pm when plates and bowls are coming back from the schools and also the huge crock and cooking pots need to be cleaned.
“As heat pumps are very efficient, they are well suited for buildings with high hot water demand. Even if the initial purchase costs are higher, the lower running costs allow to amortise the higher investment. Our cost simulation showed a satisfactory cost-effectiveness,” says Yuji Takeda, from the Takedabishi Architects Studio charged with the planning.
Can heat pumps demonstrate their merits in cold climates?
However, the city of Ninohe lies in the northeast region of Japan where temperatures easily drop to -10°C in winter and cold winds blow. There were doubts in the beginning if a heat pump system would be able to demonstrate its merits under such strict weather conditions and the concern that overall costs would increase, especially for cleaning all the equipment and for additional heating of food after peak hours.
The solution to these issues came in form of a hybrid system of Eco Cute units and heaters. In this hybrid system, developed jointly by Tohoku Electric Power and Kitanihon Electric Cable Co., 24.7 kW Eco-Cute units are combined with 8 kW heaters, in total 10 machines. The two 13.5 cubic metre hot water tanks are equipped with additional 25 kW heaters.
Supported by electric heaters, Eco Cutes also perform in the cold
The Eco Cute heat pumps normally produce 90°C hot water. If however during night when they produce the major part of the hot water, temperatures fall below 0°C, they have been set to produce 70°C hot water as to allow the Eco Cutes to work in their best efficient mode. As back up, the electric heaters at the two water tanks come in and provide the energy for heating up the water additional 15°C, so that even in very low ambient temperatures a water temperature of 85°C can be reached. The hot water tanks are furthermore covered in insulation material, protected against wind and snow and the heaters have been equipped with protective hoods.
The system has been in operation now for almost two years and has worked through the winters without any problems. The heaters have been in operation from the beginning of December to the end of March with electricity consumption in the expected range. Apart from winter time, the CO2 heat pumps satisfy the hot water supply on their own.
“Before the refurbishment, we had boilers which were work intensive to maintain. With the new Eco Cute hybrid system we do not have such worries, “ says Tadanori Yamadate, director of Ninohe's central school canteen. “With the installation of this hybrid hot water system, we have also opted for an all-electric kitchen equipment, which now together allows us easy temperature control. This has greatly improved the quality of the food preparation and the working climate as well.”
The Eco Cute hybrid system is also gentle on the local environment as carbon emissions are estimated to be cut by one third to one half.
Mr. Ito, head of the heat pump department of Kitanihon Electric Cable Co., says the trend goes to the development of heat pumps for cold climates and he believes that there will soon be Eco Cute systems that do not necessitate the assistance of heaters for the coldest times anymore. With higher volumes the prices will also drop and the move to Eco Cute will become easier for the customers. Mr. Ito estimates that Eco Cute hot water systems will find rapid uptake in colder climate regions.
Five years ago the two cities of Ninohe and Jouhouji grew together to form one large agglomeration. As their school canteens which deliver the food to 14 primary and junior high schools in the neighbourhood were obsolete, they decided to build a new central school canteen, state-of-the-art in hygiene management. The new central school canteen was finished in 2009 to produce and deliver around 2,800 meals per day. In the refurbishment of the canteen it was decided to opt for an all-electric system and to test a heat pump system for the hot water supply. The canteen has a very high hot water demand, especially in the afternoon between 2-3 pm when plates and bowls are coming back from the schools and also the huge crock and cooking pots need to be cleaned.
“As heat pumps are very efficient, they are well suited for buildings with high hot water demand. Even if the initial purchase costs are higher, the lower running costs allow to amortise the higher investment. Our cost simulation showed a satisfactory cost-effectiveness,” says Yuji Takeda, from the Takedabishi Architects Studio charged with the planning.
Can heat pumps demonstrate their merits in cold climates?
However, the city of Ninohe lies in the northeast region of Japan where temperatures easily drop to -10°C in winter and cold winds blow. There were doubts in the beginning if a heat pump system would be able to demonstrate its merits under such strict weather conditions and the concern that overall costs would increase, especially for cleaning all the equipment and for additional heating of food after peak hours.
The solution to these issues came in form of a hybrid system of Eco Cute units and heaters. In this hybrid system, developed jointly by Tohoku Electric Power and Kitanihon Electric Cable Co., 24.7 kW Eco-Cute units are combined with 8 kW heaters, in total 10 machines. The two 13.5 cubic metre hot water tanks are equipped with additional 25 kW heaters.
Supported by electric heaters, Eco Cutes also perform in the cold
The Eco Cute heat pumps normally produce 90°C hot water. If however during night when they produce the major part of the hot water, temperatures fall below 0°C, they have been set to produce 70°C hot water as to allow the Eco Cutes to work in their best efficient mode. As back up, the electric heaters at the two water tanks come in and provide the energy for heating up the water additional 15°C, so that even in very low ambient temperatures a water temperature of 85°C can be reached. The hot water tanks are furthermore covered in insulation material, protected against wind and snow and the heaters have been equipped with protective hoods.
The system has been in operation now for almost two years and has worked through the winters without any problems. The heaters have been in operation from the beginning of December to the end of March with electricity consumption in the expected range. Apart from winter time, the CO2 heat pumps satisfy the hot water supply on their own.
“Before the refurbishment, we had boilers which were work intensive to maintain. With the new Eco Cute hybrid system we do not have such worries, “ says Tadanori Yamadate, director of Ninohe's central school canteen. “With the installation of this hybrid hot water system, we have also opted for an all-electric kitchen equipment, which now together allows us easy temperature control. This has greatly improved the quality of the food preparation and the working climate as well.”
The Eco Cute hybrid system is also gentle on the local environment as carbon emissions are estimated to be cut by one third to one half.
Mr. Ito, head of the heat pump department of Kitanihon Electric Cable Co., says the trend goes to the development of heat pumps for cold climates and he believes that there will soon be Eco Cute systems that do not necessitate the assistance of heaters for the coldest times anymore. With higher volumes the prices will also drop and the move to Eco Cute will become easier for the customers. Mr. Ito estimates that Eco Cute hot water systems will find rapid uptake in colder climate regions.
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By R744.com team (@r744)
Jul 04, 2011, 16:33
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