Researchers at the University of Nottingham in the United Kingdom have demonstrated the feasibility of residential ice-source heat pumps (ISHPs) for cold climates and densely populated urban areas.

Researchers at the University of Nottingham in the United Kingdom have demonstrated the feasibility of residential ice-source heat pumps (ISHPs) for cold climates and densely populated urban areas. The system utilizes existing gas pipelines repurposed to transport water, which is used to generate heat from ice or ice slurry. This innovative approach reduces reliance on natural gas and integrates well with renewable energy sources like solar power. The proposed 7 kW system uses propane (R290) as a refrigerant and operates through a compression refrigeration cycle. It can also supply non-potable water for irrigation, sanitation, and washing. The researchers modeled the system's performance, finding it to be cost-effective, particularly when covering 39.66% of peak gas consumption energy . While slightly less efficient than water-source heat pumps, ISHPs significantly reduce water consumption by 37.56 times , making them suitable for high-latitude regions with limited water resources.

Data Extracted:

System Design and Operation:

1. Heat Source:

   • Utilizes ice or ice slurry derived from water transported via repurposed gas pipelines or seasonal rainfall.

2. Refrigerant:

   • Propane (R290)

3. Refrigeration Cycle:

   • Compressor → Condenser → Heat sink (phase change: gas → liquid) → Evaporator (absorbs heat from cold source) → Compressor restarts cycle.

4. Heat Distribution:

   • Can connect to a central heat pump system for multiple residential units, ideal for newly developed areas or residential complexes.

5. Additional Water Supply:

   • Provides non-potable water for uses such as irrigation, sanitation, and washing.

Performance Metrics:

1. Peak Gas Consumption Coverage:

   • The system covers 39.66% of peak gas consumption energy using repurposed gas pipelines.

2. Water Efficiency:

   • Reduces water consumption by 37.56 times compared to water-source heat pump systems.

3. Thermal Losses:

   • Minimal thermal losses, ensuring effective operation during peak cold periods.

4. Subscriber Coverage:

   • Ensures services for at least 39.9% of subscribers during peak demand, even in worst-case scenarios.

Key Features:

1. Repurposing Gas Pipelines:

   • Existing gas distribution networks are used to transport water for the heat pump's operation, reducing infrastructure costs.

2. Integration with Solar Power:

   • Continuous and stable operation makes ISHPs more compatible with solar photovoltaic (PV) systems compared to other heat pumps.

3. Energy Storage Solutions:

   • Off-peak energy storage systems can address consumption exceeding the 39.66% coverage limit during peak demand periods.

4. Environmental Benefits:

   • Reduces reliance on natural gas and minimizes water usage, making it sustainable for densely populated areas.

Applications:

1. Urban Areas:

   • Suitable for densely populated regions where space for traditional heat pump systems is limited.

2. Cold Climates:

   • Particularly effective in high-latitude regions with limited water resources and extreme cold conditions.

3. New Developments:

   • Ideal for newly constructed residential complexes where pipeline layouts and dimensions can be meticulously planned.

Challenges and Solutions:

1. Peak Demand Limitations:

   • Challenges may arise in servicing all subscribers during peak demand periods exceeding the 39.66% coverage limit.

   • Proposed solution: Use energy storage systems during off-peak times to manage excess demand.

2. Ice Slurry Disposal:

   • Produced ice slurry is discharged into the drainage and wastewater system by gravity.

Research Context:

1. Publication Details:

   • Paper Title: “Ice-Source Heat Pumps: Sustainable Heating Solutions for Urban Areas Utilizing Water and Gas Networks”

   • Published in: Energy and Buildings

2. Corresponding Author:

   • Ramin Mehdipour , University of Nottingham

3. Previous Research:

   • The proposed system builds on earlier work by the same research group, refining previous designs for better efficiency and practicality.