top of page
Image by the blowup

Horizontal Closed Loop System

RHI Energies has the in house capability to offer a complete turnkey package from the modelling of the ground source loop design, using the latest design software, through to the installation of the system pipe work to the Final commissioning and after sales management for horizontal, closed loop, ground source heat pump system.


Summary of Technologies

Horizontal or slinky closed loop ground source geothermal system consists of HDPE pipes laid into trenches in the ground to depths of up to 3m. The trench length can vary from 25 to 2000m by using multiple trenches.


The design of the system establishes the final quantity and lengths of trenches which is dependent upon the geology of the ground, the pipe work diameter, the thermo conductivity levels of the soil, the heat and rejection absorption requirements and finally the building load profile for the building.

The ground source pipe work system carries water from the ground (the heat collector rejecter) 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 available

  • Water to direct expansion (VRF) solutions

  • Heat recovery

  • Free cooling

  • Single or double looping systems

  • Loop depths to 200 meters so as to limit footprint of bore field

  • Domestic hot water supply

  • Solar water pre-heating

  • Ice storage cooling systems

  • Snow melt

Key Benefits

  • Design loads from 10kw to 500kw

  • Highest possible energy efficiency

  • Highly flexible system solution as modular design

  • Suitable for projects in the UK and abroad

  • Extremely low maintenance.

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

  • Low payback periods on life cycle costing analysis as highly efficient and low running/maintenance costs

  • No fumes, no fuel stores, no flues

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

  • System has no visible or noise impact as it is installed below ground and therefore it has no line of sight or acoustic screens and planning becomes simplified

  • 50 years life cycle on HDPE pipe work

  • Systems enable rebate under the Renewable Heat Incentive scheme

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

RHI Energies Offers

  • Non-fee 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 using the latest modelling software of the ground source loop system based on the building load profile

  • Hydrogeolical assessment of the geology of the ground.

  • Design confirmation indicating the size of pipe work, the number of required trenches and the lengths of pipe work required in a fully detailed design.

  • Excavation of trenches and installation of the geothermal looping

  • Installation of all external geothermal pipe work in order to connect the trenching network to the internal systems

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

  • Final pressure testing and flushing of the complete geothermal circuit

  • Filling, dosing and verifying system glycol content and quality

  • Final commissioning of the ground source system for client use

  • Dedicated installed IOMs

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

bottom of page