The solution of Saint-Gobain Rakennustuotteet Oy for heating its production facilities is the Chillquick Thermo™ heat pump.

The goal of the energy efficiency agreement driven by the Ministry of Employment and the Economy is to reduce consumption of energy in various sectors of the business life by at least 9 % by 2016. The energy efficiency program aims at significant savings in energy consumption through enhancing the energy consumption of buildings. This lowers carbon dioxide and other greenhouse emissions and contributes to preventing the climate change.

For Saint-Gobain Rakennustuotteet Oy, the energy efficiency program has been a natural incentive for intensifying their own operation. The company already operates in the same field: It produces building solutions that save energy and improve the comfort of living. The most important values of Saint-Gobain Rakennustuotteet Oy are energy conservation, friendliness to the environment, innovativeness and safety.

Saint-Gobain Rakennustuotteet Oy was looking for the most energy-efficient alternative for heating its modern production facilities. Previously, the production facilities in Forssa were heated using district heating and oil. For its new heating system, the company selected the Chillquick Thermo™ heat pump manufactured by Chiller Oy.

District heating to minimum

The Chillquick Thermo™ heat pump has been responsible for heating the production premises since the beginning of September 2009, and it was noticed quickly that the consumption of district heating had dropped to the minimum. The maintenance manager Totti Könkö of Saint-Gobain Rakennustuotteet Oy says that savings have already been achieved. This is an obvious advantage to the Forssa factory, as the company owners in the headquarters in France monitor the energy costs of the factory in addition to the other key figures. Expectations on the efficiency of the heat pump were high in the factory that manufactures mineral wool products (the product range includes ISOVER building insulation). "The heat pump would replace at least 50% of the annual consumption of district heating, in which case the repayment period would be 1 to 2 years," they calculated. "In 2008, the energy consumption of the factory was 2,300 MWh (corresponding to approximately 290,000 litres of heating oil), and in the future, we hope to cut the consumption by half," says maintenance manager Könkö. "The maximum heating capacity of our heat pump is 250 kW. We will have reached our goal if it replaces one half of our demand for heat energy," he continues. The heat pump is used to recover the process waste heat, i.e. the cooling energy generated by the manufacture of insulation wool, and the generated heat is used to heat the building. This waste heat is at a remarkably higher temperature than the heat source of a conventional terrestrial heat pump. In this way, extremely high coefficients of performance can be achieved. In this application, the coefficient of performance of the heat pump according to the dimensioning situation is almost 5. In other words, producing the heating energy, in this application 1,150 MWh, with a heat pump requires less than 250 MWh of electricity. In addition, the service water of the building is received "thrown in" from the heat pump. It is taken from the system with so-called desuperheating. The water received from desuperheating exchangers is at a temperature of around +70 to +80°C, and it is conducted to the upper part of the hot-water tank. The service-water heating coils in the tank are used to heat the actual service water and, if necessary, the existing district heating exchangers are used for final heating. The maintenance manager Könkö says that they have been very satisfied with the solution. They would keep the heat pump even if they had to choose again. "As a technology, the heat pump is very interesting, and we should follow its development also in the future." "Winter is coming and our expectations are high. We expect the device to deliver the energy savings promised at the factory. After the winter, we will be wiser and can certainly recommend the heat pump to others, as well," he thinks.

Reliability with remote monitoring

Chiller Oy invests in remote monitoring of its devices. Remote monitoring can be used the monitor the functions of a customer´s heat pump, prevent malfunctions and optimise the operation of the device. In Forssa, only a communications card, which was connected to the Internet, was added to the basic controller of the device. The communications card sends all its events and measurements to the remote monitoring server that can be accessed at any time using an Internet browser. The Chiller Service Next™ remote monitoring system is then available to all user groups without separate control-room software. The temperature level of the process waste heat changes very quickly. With monitoring, it was easy to adjust remotely the relief valve inside the device at the Forssa factory of Saint-Gobain Rakennustuotteet Oy in order to achieve an optimal and steadily safe temperature level for the device. With remote monitoring, any alarms can be forwarded to the e-mails or phones of the correct persons. Furthermore, it is possible to include so-called system alarms in the remote monitoring system that can be used to monitor temperature differences, for example. In this way, it is possible to receive an indication on the contamination of heat exchangers, for example. The system sends the customer a monthly report that shows the device utilisation rate, start-ups, alarms, service requirements etc.

CASE Saint-Gobain, Forssa, Finland

Heat pump Chiller Chillquick Thermo™ CHT-48-4D-P1-P3-P6-SHE

• Process cooling/HR power 195.8 kW at a flow of 7.8 kg/sec at a temperature level of +23℃/+17℃

• Heating power 248.8 kW at a flow of 9.9 kg/sec at a temperature level of +49℃/+55℃

• Desuperheating power 2*35.3 kW at a flow of 2*0.44 kg/sec at a temperature level of +50℃/+70℃

The heat pump has a unit with four double-circuit compressors and desuperheating exchangers. The heat pump is connected to a 3,000-litre hot water boiler that has two heavy-duty LK120 service water coils. The boiler has been divided with a compensator plate into two parts so that the upper part of approximately 1,000 litres is kept at a higher temperature using the heat from desuperheating. The building´s need for peak power is significantly higher than the power of the heat pump. Nevertheless, it is assumed that the heat pump will cover up to one half of the building's heat demand. The heat pump boiler is connected to the return side of the building´s heating system so that the heat pump always heats the water returning from the heating system. When the heat demand exceeds the capacity of the heat pump, the missing portion is covered with district heating. Service water is also pre-heated in the coils of the boiler, and district heating is used for final heating, if necessary.