Project Overview
GPJ were appointed to investigate rising energy costs and develop a new energy strategy for a large historic hotel. The existing heating plant was inefficient, with oversized gas boilers, ageing pumps, outdated controls and significant thermal losses across the existing system.
Following detailed analysis of the site’s electrical and thermal energy consumption, GPJ developed a major energy centre upgrade incorporating combined heat and power, high-efficiency boilers, thermal storage and a new site-wide control strategy.
Our Involvement
GPJ analysed historical half-hourly electrical demand and thermal energy consumption to understand how the site was actually operating. This information was used to size a 65kW CHP microturbine around the hotel’s electrical base load, maximising the opportunity to utilise both the electrical and recovered thermal energy generated by the CHP.
GPJ developed the mechanical and electrical design for the new energy centre, including three modular high-efficiency boilers, the CHP microturbine, an 8,000-litre thermal buffer vessel, new heating and hot water heat exchangers, hot water storage, variable-speed pumping and extensive modifications to the existing heating infrastructure. The design also included new BMS control panels, electrical distribution and energy metering.
GPJ produced the detailed M&E specification and design information, undertook the M&E Principal Designer role and provided technical and quality assurance support throughout delivery.
Key Project Considerations
A key element of the project was the integration of the CHP with the site’s existing solar PV generation and constrained electrical infrastructure.
GPJ developed a detailed control philosophy that continuously monitored hotel electrical demand, solar generation and CHP output. The CHP was designed to modulate against the hotel’s live electrical load while monitoring total site generation against the agreed electrical capacity. Surplus solar generation was automatically directed into immersion heaters serving the hot water and thermal buffer vessels, allowing otherwise exported electrical energy to be stored as useful heat.
The control strategy also prioritised hot water demand, managed thermal storage, weather-compensated the heating system and incorporated operating strategies for loss of mains power.
The project demonstrates the importance of developing energy systems around measured building performance and how a site actually operates, rather than simply replacing existing plant on a like-for-like basis.