Heating with ice

This technology is similar to the one described in the article "(Sea)Water used for heating purposes". Have you ever heard about heating a house with ice?

That’s what a company in the south of Germany is advertising. Several houses already use this system, for example the hotel Riva in Konstanz, Germany.

This system uses the heat which is released when cooling liquid water from 0°C further and produce ice. The amount of energy to produce ice from liquid water is 333,5 kJ/kg. This is the same amount of energy which heats water at 0°C to around 80°C. (You can easily verify this by dividing the 333,5 kJ/kg with the heat capacity of water which is 4,18 kJ/(kg*K). The result is 79K.)

To make this amount usable for heating purposes there is technical equipment necessary. These are a special storage facility, a heat pump, an air collector and a storage tank for hot water.
The purpose of storage tank is to make the heat source accessible. Here the heat is extracted by the heat pump. The interesting part of this tank comes into play when the temperature drops around 0°C and ice will start to appear. Here a special technology especially designed for this process comes into play.
Normally a pond of water starts to ice from the outside and from the top to the bottom. In this tank the ice is produced the other way round: From bottom to the top and from the middle of the tank to the outside. Therefore the liquid water has to move to the top and the tank is safe. This is due to a special arrangement of heat exchangers. Within the tank there are two of these exchangers. One extracts the heat from the water and the other will put in heat which is extracted from the surrounding air.

At the bottom of this article there is a picture which illustrates the technique. The original description can be found on the homepage of the company. Here is the link: http://www.isocal.de/solareis-komponenten.html

As every heat exchanger can be used the other way round this system has the ability to use the water as a cooling asset. In summer times, when the air in the building gets too warm, the whole cycle can work the other way round where the house is the heat source. Therefore this whole system can be used in all seasons and can be implemented for companies and residential houses.

In monetary terms there is an example given on the webpage of the company for residential houses with an initial investment cost of 32,900€ (VAT included).
Here this system is compared to a condensing boiler facility and a heating system using pellets. After 15 years the costs of the heating-with-ice-system is even lower than the costs for both other systems.
There is a small water storage tank which has a size of 90cm x 90 cm. This can be used in every household. It is estimated that the time for amortization is about 6-10 years. As in some countries there are financial helps and in case of increasing energy prices this time can even drop.

Sources:

• http://www.eisheizung.com/eisheizung.html
• http://www.isocal.de/gewerbebau/success-stories/success-stories-einzelbericht/items/5.html
• http://www.isocal.de/investitions-und-betriebskosten.html
• http://www.youtube.com/watch?v=XpFV0k4HlCY
• http://www.youtube.com/watch?v=c9unh6UQWeo