SGN currently operates approximately 240 pre-heat assets where approximately 120 of these are rated below 200kW. One challenge faced by gas distribution networks is the lack of replacement options available where small scale preheat solutions are required. Current available options are limited to small-scale boiler houses which are complex resulting in higher call-out rates and have a shorter asset life.

A number of innovation projects have been carried out looking to improve efficiencies within our network. Recently completed NIA project carried out by ProHeat “Strategic Pipeline Heat Study (NIA_SGN0106)”, investigated the operation of several types of preheating technologies, and evidenced how to optimise our alarm, control and operating philosophies to increase energy efficiency, reduce unnecessary call outs and potentially eliminate the requirement for lagging.

This led to a further NIA project “ACE (Advanced Condensing Exchanger) (NIA_SGN0124)”, which investigated conceptual designs into ACE heaters which are efficient and easy to maintain, alternatives for both water bath heater and boiler house upgrades.

While the initial ACE heater Phase 1 concept (NIA_SGN0124) was targeted for application up to 50kW, it was identified through the Strategic Pipeline Heat Study (NIA_SGN0106) project that:

• The average installed pre-heat capacity for SGN is near 200kW.
• Sites with pressure cuts of <30 bar have, on average, half the total annual operating hours as compared to pressure cuts >30 bar, some operating as little as 300 hours per year.

Building on the learnings gained in Phase 1 of the ACE development (NIA_SGN0124), an additional project request has been included to review the feasibility of increasing the capacity of the original ACE to 240 kW while also developing ACE as a retrofit for older boiler house installations. These will be covered in two individual work packages (WP), WP1 ACE 240 Heater – Conceptual Design and WP2 ACE boiler House Retrofit – Conceptual Design.

Objectives

The objectives of the project are to:

• Undertake conceptual design of ACE 240 Heater
• designed with a minimum of complexity such that existing SGN staff can resolve call-outs and undertake maintenance.
• Detailed Design Packages and PS/5 Package
• The proposed retrofit study for Petersfield will open a door for a 96% efficient boiler and provide cost-effective option to renew pre-heat assets without unnecessarily adding to complexity.
• A custom manifold will also be designed to allow two new boilers to be integrated with the existing site hot water circulation pipework.
• ACE Boiler House Retrofit will identify which components can be reused while upgrading the site to improve efficiency and meet redundancy requirements in accordance with TD/13.
• Each ACE design has been proposed with a focus on plant life of 20-30 years