Edinburgh College

To accommodate the additional electrical loads from the heat pumps, the site’s incoming electrical supply required upgrading. This included installing a higher‑capacity supply cable from the local District Network Operator (DNO) substation to a new low voltage switchboard housed within a purpose‑built enclosure.

We also rerouted the site’s main incoming cable which introduced additional challenges as the DNO was required to change current transformer ratios which affected not only the College, but also nearby households.  Because of this, we worked with stakeholders to coordinate the shutdown and complete upgrades within the outage window.

The project was carefully planned around the academic calendar, with works phased to avoid periods of peak campus activity. During pre‑construction, the delivery team worked closely with college stakeholders to understand term dates, key events and operational sensitivities, drawing on staff’s day‑to‑day experience of the campus.

This insight informed a delivery programme that protected teaching and learning, minimised disruption to staff and students, and ensured the decarbonisation works could be implemented without compromising teaching and learning activity.

Edinburgh’s climate required the heating system to deliver reliable, high‑temperature heat during prolonged periods of sub‑zero temperatures. A hybrid air source and water source heat pump configuration was selected to meet this requirement while avoiding disruptive secondary‑side modifications to existing radiators.

To ensure year-round performance, two buffer vessels act as thermal batteries to support defrosting and additional protection can be added by transferring heat from the 15 m³ thermal store into the air source heat pump circuit.  This ensures continuity of heating during extreme cold conditions.

The heat pump enclosure brought additional planning requirements including an acoustic assessment for the College and nearby receptors.

In response, an acoustic enclosure and fencing solution was created around the heat pump compound. This successfully ensures noise levels are acceptable and enabled the scheme to progress without adverse impact on the surrounding environment.

The integration of the heat pumps into the existing heating network was carefully managed through a series of phased shutdowns and controlled connections. This approach allowed sections of the system to be modified whilst maintaining heat supply across the wider campus.

By sequencing the works and coordinating changeovers between the existing gas boilers and the new electrically driven heat pumps, the transition was made without any interruption to heating availability.

The heating system serving the site’s air handling units operated in a constant flow configuration, which was typical of older systems. Because it was sized to meet peak demand, the system frequently operated inefficiently during periods of low demand.

We replaced constant speed pumps with variable speed pumps which enables the system to be more responsive and, in turn, improved overall efficiency.

The Midlothian project was designed to demonstrate the viability of electrifying heat across an entire college campus with a view towards replicating it at their other locations.  Because of this, design decisions were partly shaped by their ability to be replicated.

By retaining existing emitters, minimising invasive works and integrating new plant seamlessly with existing infrastructure, the project demonstrates how modern education buildings can be decarbonised quickly and pragmatically.

Lessons learned at Midlothian now inform the College’s approach to future campus upgrades. This model is particularly relevant to the further education sector, where capital budgets are constrained but ambitious carbon targets still need to be met.

Beyond operational performance, the project delivers lasting educational value. As a campus dedicated to engineering and renewables training, Midlothian now operates as a live system which students can study.

Anonymised real‑time performance data from the plantroom is now integrated into the College’s engineering curriculum, allowing students to analyse live system operation. This effectively establishes the retrofit as a living laboratory, supporting both operational performance and learning outcomes.

A fully integrated Building Management System (BMS) was commissioned to support continuous optimisation of heat pump performance and provide clear performance reporting.

The system enables real‑time monitoring of air source and water source heat pumps, including flow and return temperatures, electrical input, heat output and seasonal performance factors.   It also identifies and logs faults, creating predictive maintenance alerts which support long-term performance.

Demand sequencing chooses between the water and air sourced heat pumps, choosing the most efficient operation of compressors at any given time.