How the Heat Store System Works
Solahart HS Series Commercial Solar Water Heating – FAQs
Discover how the Solahart HS Series commercial solar hot water system delivers reliable, low‑cost hot water at scale. From central heat storage and drain‑back frost protection to high‑performance solar collectors and flexible boosting options, this FAQ explains how the HS Series can be engineered to your building’s needs.
-
What is the Solahart HS Series commercial solar water heating system?
The Solahart HS Series is a modular commercial solar hot water solution designed for high‑demand sites such as hotels, hospitals, apartments, factories, mining villages, and caravan parks where daily hot water usage exceeds ~1,000 litres. It combines roof‑mounted solar collectors with a centralised heat store and smart system controls, and offers electric, gas, or heat pump boosting to ensure continuous hot water in all conditions.
-
Which types of facilities benefit most?
Any site with substantial and consistent hot water loads, including hospitality, healthcare, residential multi‑dwelling, industrial, and remote or off‑grid operations. The HS Series is engineered to reduce running costs and support sustainability goals for large‑scale applications.
-
How does the HS Series work in simple terms?
olar collectors capture the sun’s energy and transfer it to a non‑potable heat transfer fluid, which stores that energy in a central heat store (storage tanks). When you draw hot water, high‑efficiency heat exchange transfers stored energy to the incoming cold water, delivering on‑demand hot water at a controlled temperature. Boosting (electric, gas, or heat pump) tops up the supply during low solar gain or peak demand.
-
What are the core components of an HS Series system?
- Solar collectors (LCS or BT models)
- Central heat store using large, insulated storage tanks
- Drain‑back control for over‑temperature and frost protection
- Solar pump skid to circulate heat transfer fluid through collectors and return it to storage
- Boosting options: electric, gas, or commercial heat pump (hybrid solar + heat pump)
-
What storage tank sizes and materials are available?
- Nominal capacities: 1,000 / 2,000 / 3,000 / 4,000 / 5,000 litres
- Materials & operating pressures:
- Carbon steel tanks for indirect heating, 5 bar operating pressure (with corrosion inhibitor)
- 316L stainless steel tanks for potable water, 8.5 bar operating pressure
- Insulation & cladding:
- 100 mm insulation with PVC jacket (indoor) or bonded aluminium cladding (outdoor)
- Scalability: Multiple tanks can be interconnected to exceed 5,000 L and improve plant room fit and redundancy.
-
What solar collector options does Solahart offer for the HS Series?
- LCS Collector: Aluminium absorber plate with copper headers/risers, coated with Mirotherm® selective surface for high solar absorption and low thermal emission.
- BT Collector: All‑copper absorber and risers, laser‑welded for maximum heat transfer, with glass wool insulation for minimal heat loss; performs strongly from low to high solar radiation climates.
-
How does the drain‑back principle protect performance and assets?
The HS Series uses automatic drain‑back: when solar gain is insufficient or the system reaches its maximum set temperature, the heat transfer fluid drains back into the heat store. This:
- Prevents over‑temperature (no wasted energy or risk to components)
- Provides frost protection without glycol‑based complexity in the collector loop
- Eliminates the need for rooftop heat‑dissipation equipment often required in fully flooded systems
-
What performance and protection features are standard?
- Complete over‑temperature and freeze protection via drain‑back
- Precise temperature control for consistent outlet temperature
- Instantaneous hot water delivery supported by central storage
- Low running costs through high solar contribution
- Engineered to site requirements with scalable modules and flexible storage layouts
-
Is the HS Series scalable for future growth?
Yes. The system is modular and expandable. You can add additional collectors and/or more storage tanks later to match increased hot water demand.
-
Can it integrate with my existing plant?
Yes. The HS Series can be configured as a solar pre‑heater to immediately cut the running costs of an existing hot water plant, or deployed as a complete replacement in new builds.
-
What boosting options are available?
Solahart supports electric, gas, or commercial heat pump boosting. Boosting can either raise the central heat store temperature or top‑up potable water temperature to your required service set‑point during low solar input or peak demand.
-
How efficient are Solahart commercial heat pumps in a hybrid solar system?
Solahart commercial heat pumps typically achieve an average COP around 4.0 under standard test conditions (20 °C ambient, 60% RH, 40 °C entering water), meaning ~75% of the energy used to generate hot water is taken from environmental heat—a strong complement to solar thermal contribution.
-
Can the HS Series be installed outdoors?
Yes. Storage tanks can be supplied with bonded aluminium cladding and 100 mm insulation for outdoor duty; PVC‑jacketed insulation is available for indoor plant rooms.
-
What operating temperatures and pressures apply to the storage tanks?
- Max operating temperature: 90 °C
- Operating pressure: 5 bar (carbon steel, indirect) or 8.5 bar (316L stainless steel, potable)
-
How does the system reduce maintenance risk on the roof?
The drain‑back design helps avoid stagnation and reduces the need for rooftop heat‑dissipation hardware required by some fully flooded solar systems, simplifying rooftop maintenance.
Technical Choices & Sizing
-
How do I choose between LCS and BT collectors?
- Choose LCS when you want a high‑performance selective surface with aluminium absorber and copper risers, ideal for sites prioritising high absorption / low emission characteristics.
- Choose BT for maximum performance across a broad climate range, with all‑copper construction and laser‑welded risers for excellent heat transfer and low losses.
-
What if my plant room has space constraints?
The HS Series uses modular storage. You can interconnect multiple smaller tanks instead of a single large tank to optimise footprint, facilitate transport and installation, and add redundancy.
-
How high can the solar pump skid circulate to the collectors?
Solar pump skid options are available to support systems with roof heights up to ~40 m (model dependent), and numbers of BT collectors ranging from small arrays up to large fields; your Solahart engineer will match the pump skid to array size and elevation.
-
Quick Technical Reference (at‑a‑glance)
- Storage tanks: 1,000 / 2,000 / 3,000 / 4,000 / 5,000 L
- Materials: Carbon steel (indirect, 5 bar), 316L stainless steel (potable, 8.5 bar)
- Max operating temp: 90 °C
- Insulation: 100 mm (PVC jacket indoor / bonded aluminium outdoor)
- Collectors: LCS (Mirotherm® selective surface), BT (all‑copper, laser‑welded)
- Protection: Drain‑back for frost and over‑temperature
- Boosting options: Electric, gas, commercial heat pump (COP ~4.0 at 20 °C ambient, 60% RH, 40 °C entering water)
-
Does Solahart provide design and engineering support?
Yes. Solahart’s technical support teams work with architects, consultants, and builders to custom design commercial solar thermal systems—from concept and specification through to commissioning.
-
Can the system be expanded later if my demand grows?
Yes. The system is scalable: add collectors and storage modules to meet future demand without replacing the entire plant.
