Project Overview:
A groundbreaking compact heat battery and heat pump system have replaced gas combi boilers in 364 space-constrained homes, improving resident safety and reducing carbon emissions. This innovative energy solution optimizes space, reduces energy costs, and minimizes maintenance requirements, making it ideal for urban high-rise apartments. With an estimated 70% annual reduction in CO₂ emissions, this eco-friendly system supports the transition to net-zero buildings. As the first UK project to eliminate gas supply in occupied high-rise buildings with minimal disruption, it sets a benchmark for sustainable housing retrofits and energy efficiency.
Problems to be addressed:
Gentoo Group, a housing association in northern England, faced a significant challenge: how to completely remove the gas supply and replace outdated combi boilers in 364 apartments across seven tower blocks—all without displacing residents.
Adding to the complexity, the new system needed to fit into the limited space of each home and be user-friendly. Traditional hot water systems and their extensive pipework were not viable, and unvented cylinders were unsuitable due to the unique building structure. The constraints demanded an innovative and efficient solution to meet the housing association’s needs.
Existing System Overview:
The Sunamp Solution:
The solution was an innovative integrated system combining Sunamp’s ultra-compact heat batteries for domestic hot water with Kensa Contracting’s small, quiet Shoebox ground source heat pumps. This system is managed through an intuitive, smart interface from Switchee, making it easy for residents to use.
The system is communally fed but locally managed, offering residents enhanced control and comfort while significantly lowering running costs. This approach provided an efficient and space-saving alternative to traditional heating systems, perfectly addressing the project’s unique challenges.
Results and Findings
- Carbon Savings: Approximately 420 tons per year, representing a 70% reduction in CO₂ emissions.
- Heating Capacity: A total of 1.26 MW, with 308 units providing 3 kW each and 56 units delivering 6 kW each.
- Storage Capacity: 364 heat batteries, each with 9 kWh capacity, for a total of 3.28 MWh of thermal energy storage.
- Heating Source: Individual Kensa Shoebox heat pumps paired with Sunamp UniQ heat batteries, connected to an open-loop ground-source system.
- Heat Pump Supply Temperature: Space heating up to 55°C and heat battery charging up to 65°C.
Impact & Conclusion: Enhancing Energy Efficiency and Sustainability
This innovative system brought significant advantages to the high-rise apartment blocks and their residents:
Enhanced Safety: Eliminating gas supplies removed the risk of gas-related explosions and carbon monoxide poisoning. Additionally, the system eradicated the risk of legionella infections.
Lower Maintenance Costs: The need for annual gas safety checks, certifications, and cylinder safety inspections was eliminated, significantly reducing ongoing maintenance expenses.
Major Carbon Reduction: The system is projected to cut carbon emissions by approximately 420 tonnes annually, equating to a nearly 70% reduction.
Minimal Disruption: For the first time in the UK, gas supplies were safely removed from occupied high-rise buildings without relocating residents. The same system can also be applied to lower-density housing, offering similar benefits.