If people address a problem with enthusiasm in an honest way, the problem will be solved step by step and they will finally achieve the ideal state. The development of Hitachi's Eco Cute involved challenges and the passion of each engineer engaged in eco-conscious development.
![[Image] Hiroshi Arita, Chief Engineer, Products Planning Division, Shimizu Home Appliance Group, Hitachi Appliances Inc.](/environment/showcase/speco_technique/ecocute/images/img_03-01.jpg)
Hiroshi Arita, Chief Engineer, Products Planning Division, Shimizu Home Appliance Group, Hitachi Appliances Inc.
How were you involved in Eco Cute?
It was decided to develop Eco Cute in 2003, and I have been involved in the project since then. There were only three people involved at that time, which was too few. Before then, I had nothing to do with Eco Cute.
For what are you responsible in the development of Eco Cute?
![[Image] Mr. Arita is talking](/environment/showcase/speco_technique/ecocute/images/img_03-02.jpg)
Hitachi already had experience with the development of electric water heaters and had accumulated expertise on core technologies of electric water-heating systems of the time. So we went forward with the development by applying them to the Eco Cute. In the project, I worked on improving the usability of the product, such as the performance of hot water supply and smooth hot water flow.
What was a difficult point in the development of Eco Cute?
It was hard to solve a problem specific to Eco Cute when applying the water heating function of electric water heaters to the Eco Cute.
First of all, the easiest and most efficient way for the Eco Cute to boil water is to do so at as low a temperature as possible. However, with the water heating function, only the heat of the high-temperature hot water in the tank is sent to the bathtub instead of the hot water itself. Therefore, the hot water in the tank is cooled to a medium temperature, causing a problem because it is not boiled efficiently. Then, we made an outlet for water at medium temperatures only to use this water for hot water supply preferentially, and solved the problem.
Were there any competing products with the water heating function?
No, they tended to use electric heaters to keep the preset temperature, approx. 40 degrees, based on the concept of thermal insulation. Eco Cute could not reheat cooled hot water in general. Therefore, Hitachi equipped the Eco Cute with the water heating function for the first time in the industry.
![[Image] Mr. Arita is talking](/environment/showcase/speco_technique/ecocute/images/img_03-03.jpg)
![[Image] High pressure showers made available by direct mains pressure!](/environment/showcase/speco_technique/ecocute/images/img_03-04.jpg)
What inspired you to develop the water service direct pressure system?
Many Eco Cute customers are 'high-end users' and often use a multifunction showerhead that offers a massage function with high pressure. Some of these customers pointed out that the water pressure of shower was weak, and we developed the 'water service direct pressure system' to manage to meet their needs. Before that, we persuaded them by saying that 'this is a fundamental issue of the Eco Cute'.
What are the principles of the mechanism behind the water service direct pressure system?
For the conventional Eco Cute, reducing the pressure of hot water was needed structurally, because water was supplied to the tank before it was sent to the showerhead. On the other hand, with the water service direct pressure system, since the tap water is sent to the showerhead after it is boiled through the heat exchanger, if the pressure of the tap water is higher, that of the water flushed out of the showerhead will also be higher.
Are there any other unique technologies?
![[Image] Mr. Arita is talking](/environment/showcase/speco_technique/ecocute/images/img_03-05.jpg)
Yes, I would like to tell you about the 'tank reheating system', which is a feature of the multifunction type Eco Cute with floor and bathroom heating functions.
Since we use a principle which is the same as the water heating function for heating operations, if the operation continues, heating starts lagging behind little by little, as the temperature of the hot water in the tank drops. To prevent this, we developed a system to supply the heat of hot water boiled in the heat pump unit preferentially to hot water for heated floors and bathrooms, and then return the surplus heat to hot water in the tank.
Although this is a complex structure, we have become to be able to maintain the temperature of hot water in the tank, heated floor and bathroom.
Do you think that you can further improve upon the efficiency of Eco Cute?
Eco Cute can boil water at up to approximately 90 degrees, but this is wasteful from the viewpoint of energy saving, because the full operation of the heat pump results in inefficient energy usage, which does not lead to eco-consciousness.
Hitachi has set the minimum temperature for boiling water at 65 degrees. If setting it lower than this, we will have a problem in that the hot water will tend to run out easier, because more hot water will be used without adding water for adjustment to lower the temperature in the kitchen or bathroom.
So the difficult point is how we can save energy by lowering temperatures to boil water, balanced with the issues explained earlier.
![[Image] Mr. Arita talks beside a Eco Cute](/environment/showcase/speco_technique/ecocute/images/img_03-06.jpg)
So, do you have any good ideas for it?
I think that the key point is in how we can match the functions to the hot water usage of users. The 'learning function' of Eco Cute has been added based on this idea after much trial and error. We now check a week's worth of hot water usage of users to calculate the necessary amount of hot water, and determine the temperatures to boil water based on the results gained.
Are there any eco-conscious points in its manufacturing?
![[Image] Using cardboard boxes as packaging materials](/environment/showcase/speco_technique/ecocute/images/img_03-07.jpg)
Yes, for the test process using tap water as actually used by users with Eco Cute in the manufacturing line, we use several thousand litres of tap water per day. If we discard all of this, it will be a waste of resources. So we are reusing it as secondary clean water for development tests, toilets and so on. In addition, we changed the packing materials from wooden boxes to cartons, except for the bottom plate for the hot water storage tank unit.
What are future trends for Eco Cute?
Judging by the fact that the Japanese government is encouraging the broad use of Eco Cute, setting a goal to install 5.2 million units in Japan by 2010, I think that the replacement of the existing water heaters with Eco Cute will be promoted with the popularisation of all-electric homes. However, the fact that the price is higher than that of a gas water heater is a problem in promoting the use of Eco Cute.
Moreover, we need to reduce the total weight of the main body. This means that we have to reduce the size and weight, if possible, to the extent that one or two workers can easily install the Eco Cute. Thus cost reduction, downsizing, weight saving and performance improvement are major challenges.
What are the prospects for the achievement of these goals?
My opinion is that unified efforts among related industries will be required, for example, with an approach to make a menu of electric rates for the reduction of total running costs in co-operation with power companies and so on. Practical moves have been promoted by the manufacturers, by trying to standardise the construction techniques for equipment and producing standard materials for on-site construction in order to save the workload required.
I think that we need to further improve the penetration and performance of Eco Cute under these efforts.
Thank you very much for your useful information and kind cooperation today!
![[Image] Hiroshi Arita, Chief Engineer, Products Planning Division, Shimizu Home Appliance Group.](/environment/showcase/speco_technique/ecocute/images/img_03-08.jpg)
