Within every PRMS, gas pressure reduction causes a rapid temperature drop due to the Joule–Thomson effect. Without preheating, this cooling can lead to ice formation, hydrate build up, corrosion, equipment damage and inaccurate metering.
Traditionally, preheating is achieved through direct fired gas boilers. While functional, these systems consume significant volumes of natural gas and create high operating costs. Rising energy prices and increasing pressure to reduce emissions prompted the operator to review the efficiency of its heating system.
The objective was clear. Reduce auxiliary gas consumption, lower operational costs, and improve environmental performance without compromising reliability.
The PRMS required consistent and controlled gas preheating before pressure reduction. Any interruption to this process would risk:
The operator needed a solution that could:
The operator installed a hybrid system combining existing boilers with a Robur GAHP A 35 kW gas absorption heat pump.
Unlike conventional boilers, the GAHP unit uses natural gas to transfer heat from ambient air through a water ammonia absorption cycle. This approach significantly increases gas utilisation efficiency. The system achieves a Gas Utilisation Efficiency of up to 172 percent when compared with the calorific value of the gas consumed.
The heat pump provides base load preheating, while existing boilers remain available for peak demand support.
The installation included:
The solution required minimal electrical input, below 1 kW during operation, which avoided upgrades to the existing electrical infrastructure.
The performance comparison was measured over 196 operating days.
Existing Boiler System
Boilers + GAHP A 35 kW
The result was a 46 percent reduction in total operating costs.
Gas self consumption fell by approximately 50 percent. Although the system introduced a modest electrical demand, overall savings remained substantial.
The installation delivered measurable environmental improvements:
Flow temperatures up to 65 degrees Celsius were achieved, with reliable operation even at low ambient temperatures. Defrost cycles were short and did not interrupt performance.
The technology has been implemented in more than 140 PRMS installations in Italy, operated by major gas distribution companies. The results consistently demonstrate improved energy performance, lower emissions and dependable operation.
This case demonstrates how upgrading the preheating stage within a gas pressure reduction and metering station can significantly improve operational efficiency.
By integrating gas absorption heat pump technology alongside existing boilers, the operator reduced costs, improved environmental performance and strengthened long term infrastructure resilience.
For gas distribution networks seeking measurable efficiency gains without compromising reliability, gas absorption heat pumps provide a proven and scalable solution.