Public Utilities in L&uuml;bbecke use R290 for economical and environmentally friendly cooling

Wilhelm Schriefer GmbH has designed a cooling unit using propane for the public utilities in Lübbecke, Germany. The environmentally friendly system supplies the cooling demand for the building air-conditioning and for the server room cooling, all whislt reducing operating costs.

The Lübbecke public utilities were looking for a new cooling system for the air-conditioning of their building as well as the cooling of the server room. The refrigeration contractor Wilhelm Schriefer GmbH offered an environmentally friendly solution with a brine cooling unit using the natural refrigerant propane. Based on the estimated refrigerant charge of 2,5 kg, various safety precautions were taken, including the outdoor installation of the unit on the roof of the public utilities building.

R290 cooling unit reduces operating cost and amortisation time

The system realised by Schriefer demonstrates that without any great difficulty, it is possible to design a cooling unit with propane in accordance with local and national safety requirements. What is more, the R290 unit helps to reduce operating costs and in light of current discussions about a possible ban on certain HFC refrigerants, guarantees a high level of investment security.

A suction line heat exchanger improves the efficiency of the system as the increased enthalpy difference at the same refrigerant charge allows the absorption of more heat energy. The achieved cost savings pay off the investment for the heat exchanger within one year.

According to Karl Huber, Managing Director of HKT Huber-Kältetechnik-GmbH: “The slightly higher initial investment cost will be amortisised in less than three years.”

Components in the cooling cycle

All the components needed for an R290 cooling plant are readily available on the market. For this particular Lübbecke unit, the following were sourced:

Compressor: Semi-hermetic reciprocation compressor, type HS 32 2/8P by HKT Huber-Kälte-Technik GmbH.
Condenser: Condenser by Güntner designed for outdoor installation.
Expansion valve: Electronical expansion valve by Alco, controlled by a microprocessor.
Cooling medium: A water-glycol-mix is used for cooling.
Evaporator: A plate heat exchanger for dry expansion by VAU.