Metropolitan Powered Trench Cooling Units are fan-assisted trench cooling units from SPC, recessed into the floor beneath full height glazing to cool the room in summer and, as 4-pipe units, heat it in winter. EC/DC crossflow fans draw warm room air into the trench, pass it across the heat exchanger and blow the treated air towards the window, with fan speed set by a 0-10V signal from a BMS or room controller.
Manufactured in Leicester by S & P Coil Products Limited and independently tested to BS EN 16430, Metropolitan Powered Trench Cooling Units suit commercial, public and residential buildings with large glazed areas and high solar gains, including offices, reception areas, schools, hotels and restaurants. They fit screeded or suspended floors, in a 360 x 150 mm standard size or a 270 x 205 mm narrow size and 21 standard lengths, with bespoke sizes on request.
EC/DC fans
Crossflow fans with 0-10V speed control
Cool and heat
4-pipe for both, or 2-pipe for cooling only or changeover
BS EN 16430
Performance independently tested to BS EN 16430
Made in Leicester
Manufactured and supported by SPC in the UK
551 to 2,391 W
Cooling per unit at 6/10°C chilled water, 25°C room air and medium fan speed, across both sizes
2 or 4-pipe
4-pipe units cool and heat from separate circuits. 2-pipe units suit cooling only or seasonal changeover systems
150 or 205 mm
Unit height: 360 x 150 mm standard or 270 x 205 mm narrow, to suit the floor build-up
21 lengths
From 1,100 to 3,100 mm in 100 mm steps, joined with flangeless end plates for continuous runs
What are Metropolitan Powered Trench Cooling Units?
A Metropolitan Powered Trench Cooling Unit is a black powder coated steel casing set into the floor, holding a heat exchanger of copper tubes expanded into aluminium fins, EC/DC crossflow fans with finger guards, a stainless steel drain tray under the coil and a roll-up grille that sits level with the finished floor. Each unit runs on a 230 V single phase supply, and the output is controlled by the speed of the fans.
The unit is installed beneath the glazing with the heat exchanger on the window side. In cooling mode, the fans draw warm room air into the trench, pass it across the chilled water coil and blow the cooled air towards the window, setting up a circulation that keeps treating the warm air in the room. 4-pipe units also heat from the same trench, countering cold down-draughts from the glazing in winter.
Metropolitan Powered Trench Cooling Units beneath the arched windows at The Orangery at Aynho Park, Oxford
What sizes do Metropolitan Powered Trench Cooling Units come in?
Metropolitan Powered Trench Cooling Units come in two sizes, each in 21 standard lengths from 1,100 to 3,100 mm in 100 mm steps. Longer runs are made by joining units end to end with flangeless end plates.
| Unit | Width (mm) | Height (mm) | Width over feet (mm) |
|---|---|---|---|
| Standard | 360 | 150 | 407 |
| Narrow | 270 | 205 | 317 |
Bespoke widths, heights and lengths, curved sections and grilles, and corner kits with angled sections and mitred corner grilles are available on request.
Planning trench cooling for a glazed building? Read our guides: Why Trench Heating is Ideal for Modern Buildings and How Do You Stop Cold Down-Draughts from Full Height Glazing? You can also see the full SPC trench heating and cooling range.
How do Metropolitan Powered Trench Cooling Units perform?
Output depends on the unit size and length, the water temperatures and the fan speed, so a run of Metropolitan Powered Trench Cooling Units can be sized to the solar gains and heat losses along the glazing.
- Cooling outputs published at 6/10°C and 13/17°C chilled water and 25°C room air, at low, medium and high fan speed
- Up to 2,968 W of cooling from a 360 x 150 mm unit, 3,100 mm long, at 6/10°C chilled water and high fan speed
- Heating outputs (4-pipe units) published at 80/60°C and 50/40°C water and 20°C room air; 2-pipe outputs on request
- Sound pressure level below 30 dBA at 2 m, at medium fan speed
Where can trench cooling units be installed?
Metropolitan Powered Trench Cooling Units suit indoor spaces with large glazed areas, as single units or continuous runs.
- Screeded (concrete) or suspended floors, with levelling screws at each corner and adjustable support feet
- Each unit needs its own 230 V supply, plus control wiring for a BMS or room controller, and a drain connection where condensate is expected
- Grilles suit occasional foot traffic, not point loads such as chair legs
- Not for doorways or areas of constant footfall, or outdoors
Full cooling and heating output and water pressure drop data for both sizes and every length is in the Metropolitan Trench Heating and Cooling brochure.
Metropolitan Powered Trench Cooling Unit grilles, controls and options
Metropolitan Powered Trench Cooling Units are supplied as standard with an anodised aluminium roll-up grille and a matching trim for the edge of the casing. The double-T profile blades give a free area of 60%.
Grilles and trim come in satin silver, black and a range of Anolok bronze, gold, umber and blue-grey finishes. Stainless steel grilles are available on request (grille trim is not available in stainless steel). Roll-up grilles suit occasional foot traffic, but not point loads such as chair legs.
Metropolitan Powered Trench Cooling Units use EC/DC crossflow fans, so the output is controlled on the air side by fan speed. Water side valves can also be supplied where the project calls for them.
- 4-pipe units: separate cooling and heating circuits in one heat exchanger, each with its own connections. Looking towards the window, the heating pipes and electrical connections are at the left hand end and the cooling pipes at the right hand end
- 2-pipe units: the whole heat exchanger is one circuit, for cooling only or for seasonal changeover between heating and cooling, controlled centrally by a controller or BMS
- 0-10V control: fan speed is continuously modulated by a 0-10V signal from the building management system (BMS) or a room mounted controller, or the fans can be switched on and off
- Manual setting: fan speed can be set on site with the on-board rotary potentiometers
- Room thermostats: SPC supplies wall mounted room thermostats, including SPC Modulo
- Connections: flexible hoses with integral isolating valves are available
Every Metropolitan Powered Trench Cooling Unit has a stainless steel drain tray under the coil, extended under the cooling connections, with a 12 mm copper drain pipe at the cooling end. If the chilled water is below the dew point of the room air, condensate can form on the coil and collects in the tray, so a drain should be connected to run it to waste. Higher chilled water temperatures can be used to avoid condensate forming. If a condensate pump is needed, it is often best fitted to a common sump outside the units, so one pump can serve several units.
Bespoke widths, heights and lengths, curved sections and grilles, and corner kits with angled sections and mitred corner grilles are available. Contact SPC to discuss project-specific requirements.
Each unit arrives fully assembled, with transverse bracing and a protective cover to keep in place while the floor is finished. The grille and trim are packed separately and fitted once the unit is installed. Water connections can enter from the front or the side, but units butted together in continuous runs need their connections made from the front. In a screeded floor, the pipework, drain and power and control cables are brought into the casing before the screed is laid.
Project support from SPC: from survey to commissioning
SPC manufactures and supplies Metropolitan Powered Trench Cooling Units for installation by your chosen mechanical and electrical contractor, and supports the project at every stage. Our Trench CPD is CIBSE approved and can be booked for your practice.
Site surveys
SPC can visit site to review trench positions, dimensions and layout before order.
Selection and layout
Send us your drawings and design conditions and SPC will select unit sizes and lengths.
Trench CPD
Our CIBSE approved CPD, Design Considerations for Trench Heating, can be delivered to your practice.
Area Sales Managers
Your local SPC Area Sales Manager is on hand for questions, site visits and installation queries.
- Ready for site: each unit is labelled with its serial number, model reference and site reference, and arrives with a protective cover to keep in place until the grilles are fitted.
- Installation, operation and maintenance: IOM 84, the Metropolitan Cooling Trench manual covering installation, commissioning, maintenance and fault finding, is supplied with every unit.
Specifying Metropolitan Powered Trench Cooling Units
Unit selection from SPC and a free BIM object for your model.
Get a unit selection
Send us your drawings and design conditions and SPC will select Metropolitan Powered Trench Cooling Unit sizes and lengths for your project.
Download BIM objects
Add Metropolitan Powered Trench Cooling Units to your BIM model. The BIM object is free to download from SPC on bimstore, alongside the rest of the SPC range.
SPC trench heating and cooling in UK projects
SPC trench heating and cooling has been installed beneath full height glazing in buildings across the UK, including offices, schools, libraries, museums, hotels, restaurants and visitor centres. Metropolitan Powered Trench Cooling Units were chosen for The Orangery at Aynho Park in Oxford and the teaching rooms at Berkhamsted Sixth Form in Hertfordshire, and other SPC trench projects include 8 Salisbury Square in London, 42 Park End Street in Oxford, the Museum of Two Halves in Wrexham, Hanley Library in Stoke-on-Trent, 244-254 Cambridge Heath Road in London, The Grand York Hotel, Archway Tower in London and the Midlands Goods Shed at King’s Cross. See SPC’s projects.
Metropolitan Powered Trench Cooling Unit specification summary
| Detail | Spec |
|---|---|
| Type | Fan-assisted (powered) trench cooling unit with EC/DC crossflow fans: 4-pipe (cooling and LTHW heating) or 2-pipe (cooling only or changeover) |
| Sizes | Standard: 360 mm wide x 150 mm high (407 mm over feet). Narrow: 270 mm wide x 205 mm high (317 mm over feet) |
| Lengths | 21 standard lengths from 1,100 to 3,100 mm in 100 mm steps; longer runs joined with flangeless end plates |
| Cooling output | 551 to 2,391 W per unit at 6/10°C chilled water, or 327 to 1,396 W at 13/17°C, with 25°C room air and medium fan speed, depending on size and length (4-pipe units); 2-pipe outputs on request |
| Heating output (4-pipe) | 475 to 2,273 W per unit at 80/60°C water, or 241 to 1,122 W at 50/40°C, with 20°C room air and medium fan speed, depending on size and length |
| Fans | EC/DC crossflow fan assemblies with finger guards on the inlet side; continuous modulation from a 0-10V signal, or on/off control; on-board rotary potentiometers |
| Sound | Sound pressure level below 30 dBA at 2 m, at medium fan speed |
| Electrical | 230 V single phase supply to each unit, connected at the heating pipe end; 0-10V control wiring from a BMS or room controller |
| Heat exchanger | Copper tubes expanded into aluminium fins, in galvanised sheet steel tubeplates, with a vent plug; pressure tested to 22 barg, air under water |
| Water connections | 15 mm plain copper, front or side entry; on 4-pipe units the heating and cooling connections are at opposite ends |
| Condensate | Stainless steel drain tray under the coil, extended under the cooling connections, with a 12 mm copper drain pipe at the cooling end |
| Casing | Minimum 1.2 mm mild steel, black powder coated, with knock-outs for pipes and cables, levelling screws at all four corners, adjustable support feet, transverse bracing and a protective cover |
| Grilles | Anodised aluminium roll-up grille with stainless steel springs and plastic spacers, 60% free area, with matching trim; stainless steel grilles on request |
| Grille finishes | Satin silver, black and a range of Anolok bronze, gold, umber and blue-grey colours |
| Floors | Screeded (concrete) or suspended floors |
| Controls | Air side by fan speed; optional water side control valves, wall mounted room thermostats including SPC Modulo, and flexible hoses with integral isolating valves |
| Bespoke options | Bespoke widths, heights and lengths, curved sections and grilles, corner kits with angled sections and mitred corner grilles |
| Testing | Independently tested to BS EN 16430 1 |
| Manufactured | Leicester, UK, by S & P Coil Products Limited (ISO 9001:2015) |
1 EN 16430: European performance test standard for trench convectors and fan assisted convectors.
Full cooling and heating output and water pressure drop data for every size and length is in the Metropolitan Trench Heating and Cooling brochure.
Discuss your trench cooling project
Send us your layout for a Metropolitan Powered Trench Cooling Unit selection for your office, reception, school, hotel, restaurant or public building, request a site survey or book the Trench CPD. Call +44 (0)116 249 0044, email spc@spc-hvac.co.uk or use the form below.
Frequently Asked Questions
Trench heaters, such as Metropolitan Natural Trench Heaters and Metropolitan Powered Trench Heaters, connect to a heating system only. Trench cooling units, such as Metropolitan Powered Trench Cooling Units, have fans and a heat exchanger that takes chilled water, with a drain tray for any condensate, and 4-pipe units add a separate heating circuit so the same trench can cool in summer and heat in winter. SPC also makes Metropolitan HC trench heating and cooling, and can advise which suits your project.
A 4-pipe Metropolitan Powered Trench Cooling Unit has separate cooling and heating circuits within one heat exchanger, each with its own flow and return connections at opposite ends of the unit, so it can be supplied with chilled water and hot water at the same time. A 2-pipe unit has a single circuit: it can be used for cooling only, or on a changeover system where a central controller or BMS switches the building between heating and cooling with the seasons.
Yes. Heating outputs for 4-pipe Metropolitan Powered Trench Cooling Units are published at 50/40°C water as well as 80/60°C, with up to 1,122 W from a 360 x 150 mm unit, 3,100 mm long, at 50/40°C, 20°C room air and medium fan speed. 2-pipe units can run on a changeover system, with the chiller, boiler or heat pump controlled centrally by the BMS. For outputs at other water temperatures, contact SPC’s sales team.
It depends on the chilled water temperature. Every Metropolitan Powered Trench Cooling Unit has a stainless steel drain tray under the coil. If the chilled water is below the dew point of the room air, condensate can form on the coil and collect in the tray, so the drain pipe should be connected to run it to waste. Systems designed with higher chilled water temperatures can avoid condensate forming, and may not need drainage pipework. Where a condensate pump is used, it is often fitted to a common sump outside the units so one pump can serve several units.
Yes. LTHW (low temperature hot water) and LPHW (low pressure hot water) both describe the wet heating systems the heating circuit of a 4-pipe Metropolitan Powered Trench Cooling Unit connects to, and SPC’s trench literature uses LPHW. The cooling circuit connects to chilled water (CHW), with cooling outputs published at 6/10°C and 13/17°C chilled water and 25°C room air.
Each Metropolitan Powered Trench Cooling Unit needs a 230 V single phase supply, and an on-board power supply runs the EC/DC fans. Every unit needs its own supply, even where several units follow one thermostat, and each unit must be earthed. Fan speed is set by a 0-10V signal from the building management system (BMS) or a room mounted controller, or by hand with the on-board rotary potentiometers. Water side valves can be added, though control by fan speed is recommended.
Metropolitan Powered Trench Cooling Unit roll-up grilles are suitable for occasional foot traffic. They should not take point loads such as chair legs, and trench units should not be fitted directly in front of doorways or in areas of constant footfall, where there is a risk of damage and debris from footwear.
Lift the roll-up grille and clean the heat exchanger with a vacuum cleaner or compressed air, more often in dusty areas, and clear any debris from the casing and fan guards. Clean the fans and fan housings with air or a dry cloth only, never water or spray, as the motors contain electronic parts, and keep moisture away from the electrical section. The fans have sealed for life bearings, and the water in both circuits should be treated with an inhibitor that is compatible with copper. Full guidance is in IOM 84.
Yes. A Metropolitan Powered Trench Cooling Unit BIM object covering both unit sizes is free to download from SPC on bimstore. Dimensional drawings for both sizes are in the brochure.
