Ammonia heat pump recovers waste heat at Alfa Laval production plant

Alfa Laval is one of the world’s largest heat exchanger suppliers, supporting customers with products that boost energy efficiency and performance in their processes. At their Gunnesbo site in Lund, south Sweden, Alfa Laval is also leading the industry in heat recovery. Since 2013 the low temperature waste heat that is generated in the component production has been recovered via an innovative ammonia-based heat pump system.

DATE 2024-01-12

This heat pump solution is able to meet the heating requirements of the entire factory and corporate headquarters. The waste heat alone is able to accommodate both space heating and hot water demand. This not only avoids exposing the environment to roughly 146 metric tons of CO₂ per year, but it also just makes great business sense. Prior to the heat pump installation, Alfa Laval purchased around 3,700 MWh of district heating. Today that number can reduce by an estimated 85% thank to process heat recovery. In other words, the investment paid for itself in under three years.

Double efficiency, easily implemented with Ammonia as refrigerant

Taking the sustainability further it was also important to avoid selecting a refrigerant with possible negative impact on climate or environment. The demand was to select a natural and future-proof refrigerant. It was then found possible to obtain a heat pump system with twice the efficiency, versus using existing off-the-shelf commercial system, when applying an industrial system with the natural and future-proof ammonia as refrigerant.

Lower charge with semi-welded plate heat exchangers

The heart of the newly designed system is a flooded semi- welded evaporator, combined with an Alfa Laval U-turn separator. It absorbs the thermal energy of the oil cooling system, which is heated to around 40°C in the factory’s plate production pressing operations. The heat pump after compression delivers the heat from the semi-welded condenser to the buildings’ heating-water circuit, thus boosting the water temperature to 65°C. The system is keeping the ammonia filling to a minimum benefitting these compact, high efficiency semi-welded plate heat exchangers and thus only needs 40 kg of ammonia. In total, the heat pump has a heating capacity of 827 kW.

Really practical

Alfa Laval is using this successful project as a showroom for customers, organizations, and employees to see the benefits for themselves.

Major equipment in the plant

Sabroe reciprocating ammonia compressor
Witt high pressure float valve
Alfa Laval MK15-BW semi-welded plate evaporator, equipped with U-turn ammonia separator module
Alfa Laval M10-BW close approach semi-welded plate condenser