top of page
Image by Pawel Czerwinski

Horizontal Closed Loop System

RHI Energies offers a complete turnkey package from the modelling of the ground source design through to the installation of the system and the final commissioning and after sales management for horizontal closed loop ground source heat pump systems.

Starting with client consultations and project feasibility reviews RHI Energies can model a geothermal concept to a fully functional installed system with design and build guarantees.


Summary of Technologies

Horizontal or slinky closed loop ground source geothermal systems consist of pipes laid into trenches in the ground to depths of up to 2m. The trench lengths can vary from 100 to 2000m using multiple trenches.


The final quantity and lengths of trenches are dependant upon the geology of the ground, the thermo conductivity levels of the soil, the heat and rejection absorbtion requirements, and finally the load profile for the building.

The ground source pipe work system carries water from the ground (the heat collector rejector) to a high efficiency ground source heat pump. This provides the building with either hot water for the heating systems or domestic hot water for washing purposes, and then chilled water for cooling.

The heat pump takes the energy that has been stored from the ground via the ground loops and provides hot water to the building. The heat pump can then be switched into “reverse cycle” mode and will reject heat energy into the ground loops so as to provide cooling to the building during the summer months.

System Options

  • Simultaneous heating and cooling heat pumps

  • Water to direct expansion (VRF) solutions

  • Heat recovery heat pumps

  • Passive and active free cooling options

  • 60 degree C domestic hot water supply

  • Solar water pre-heat for ground loop optimisation.

  • Hybrid systems optimising dry coolers

  • Integrated ice storage cooling capabilities to reduce peak loads

Key Benefits

  • Design loads from 10kw to 500kw

  • Highest possible energy efficiency

  • Highly flexible system solutions as modular design

  • Suitable for a high percentage of projects in the UK and abroad

  • Extremely low maintenance

  • Efficiency of system can be guaranteed all year round as underground temperature is constant compared to air cooled systems that have variable ambient temperatures

  • Low payback periods because of efficiency and low running/maintenance costs

  • No fumes, no fuel stores, no flues

  • No building structural requirements (or structural costs ) to support geothermal systems as these are all installed below ground and there is no requirement for large internal plant spaces or roof plant areas

  • No visible or noise impact on the system as it is installed below ground and there are therefore no line of sight or acoustic screens resulting in simplified planning

  • Systems are allowable under the Enhanced Capital Allowance Scheme

  • Closed loop systems do not have the Environmental Agency regulatory controls that open loop systems do. Therefore the closed loop systems are generally faster in both design and installation

RHI Energies offers

  • Early evaluations by project so as to provide key information to clients such as geological viability, size and costs of horizontal systems

  • Assistance with C02 and energy assessment for planning

  • In-house modelling of the ground source loop system based on the building load profile

  • In-house hydrogeolical assessment of the geology of the ground.

  • Confirmation of specification of system requirements and fully detailed designs

  • Excavation of trenches and installation of the geothermal looping

  • Installation of all external geothermal pipe work so as to connect the trenching network to the internal systems

  • Supply and installation of the ground source heat pump hydraulic circuit including valved header arrangements, heat pumps, geo circulation pumps, pressurisation sets, dosing systems, expansion vessels etc

  • Final pressure testing of the complete geothermal circuit

  • Filling , dosing and verifying the water system quality

  • Final commissioning of the ground source system for client use

  • Dedicated installed IOMs

  • Training of the client and representatives in the operation of the system and equipment

bottom of page