The way ahead is smaller, smarter and energy efficient. BSD reviews the options
Air source heat pump
A range of air source heat pumps aimed at hotels, schools, hospitals and apartment blocks has been launched in the UK by Stiebel Eltron. The WPL 34, 47 and 57, at 1.5m tall, can be positioned on roofs, which means they are ideal for city sites where there is no ground level area available.
Thanks to a cascade circuit, up to four pumps can be linked together to provide higher heat outputs of up to 168kW, so that the solution can be tailored to the building.
Biomass boiler
Wood Energy has unveiled a range of Hargassner biomass boilers, for which it will be the sole UK supplier. Initially it will supply boilers between 70kW and 100kW, aimed at primary schools, community centres and country estates, with plans to expand the range later.
All the boilers, which burn wood chip or pellets, have fully automatic ignition, automatic heat exchanger cleaning systems and ash extraction. The cleaning system helps the boilers to achieve high levels of efficiency all year round, according to the manufacturer, Austrian firm Hargassner.
Prefab boiler plant
Pain-free plant room installations are promised by Evinox, which can now supply its Gemionox THI 10-50 range in a prefabricated unit. The units can be made with between three or eight of the 50kW boilers connected in cascade and can supply power from 9.7kW up to 420.8 kW for the eight-boiler unit.
Containing shunt pumps, a controller that switches on the boilers as required, a low loss header and a built-in air and dirt separator, the compact assembly comes with right- or left-hand hydraulic connections, drip collector and drain pipe with safety components already installed. The weatherproof casing means the boilers can be located outside.
Energy centres
SAV LoadTracker is a new system which allows CHP and heat pumps to work together to get the best levels of efficiency for production of electricity and heat.
SAV Modules will supply systems using Danish firm EC Power’s XRGI 15 CHP unit in multiples. The micro CHP modules, powered by a Toyota gas-fired engine, are up to 92% efficient according to the manufacturer, and can provide 6-15.2kW electricity and 17-30kW heating.
When necessary LoadTracker switches on the heat pumps to complement the CHP units, which are powered by green electricity from the CHP rather than from the grid.
Cylinders
Schuco International has updated its range of stainless steel domestic hot water cylinders suitable for use on unvented and open vented hot water systems, with 200l and 300l twincoil cylinders available.
The indirect heat exchange surfaces are designed to provide rapid heat-up. For a 200l indirect cylinder it takes 33 minutes to heat water from 15 to 65C, and 24 minutes to regenerate 70% of the contents.
The units incorporate a 3kW electric immersion heater as a back-up for summer use.
When the unit is supplied for unvented applications, it comes with all the safety equipment to comply with legislation governing the installation of such systems.
Small is beautiful
By Jonathan Tedstone
Commercial heating systems have evolved almost beyond recognition within the last decade as condensing boiler technology has become the norm alongside the steady development of LZC (low/zero carbon) technologies, together with improvements in both building design and building fabric.
Until recently, boilers for commercial or industrial use were significantly larger than domestic units, both in size and output. Now, however, there are low output commercial boilers that are perfectly suitable, if not preferable, for larger domestic or light commercial applications such as primary schools, large restaurants or pubs, small hotels or sports halls and care homes for the elderly.
These boilers are of exactly the same construction as higher output commercial models but, having been designed for plant room service, they are more robust than most domestic equivalents, and considerably more lightweight than one might expect from a commercial appliance.
Space-saving solutions
Wall-hung commercial boilers are now available with outputs up to about 115kW. They can weigh as little as 58kg and be only 480mm wide. They often cater for a wide choice of flue options for single and modular applications, making them much easier to manoeuvre and install. The Paramount Two wall-hung condensing boiler from Potterton Commercial, for example, is available in 30, 40, 60 and 80kW outputs and is on the Energy Technology List (ETL). This is part of the government’s Enhanced Capital Allowance (ECA) scheme which offers tax incentives to businesses that invest in energy-saving equipment.
Many commercial boilers have been developed with relatively sophisticated integral electronic control panels, as well as having the added capability of linking to building energy management systems. These can be monitored remotely or even offsite.
As commercial boilers have reduced in size, space and energy saving ideas have developed, such as prefabricated modular systems using wall-hung condensing boilers. Installation time is minimised by offsite preassembly incorporating pumps, pressurisation system and heating controls. This removes the possibility of parts being lost during construction or delivery, eliminating waste, additional expense and the environmental impact of reordering missing parts. LZC technologies such as solar thermal can easily be integrated into these systems too, providing an energy efficient heating solution for commercial and large domestic applications.
Jonathan Tedstone is LZC product manager for Baxi Commercial Division.
A heat pump needs brains
By Philip Ord
A VRF ground source heat pump air-conditioning system can be a more effective way to heat and cool a building than the traditional boiler in the basement and chiller system on the roof.
Heat pump developments now offer further energy saving potential, such as water heating systems that bolt onto an air-conditioning system, negating the need for a traditional boiler and providing all the hot water.
Yet one area that can have a dramatic effect on both the performance and energy use of any system is seldom given the consideration it deserves: the controls. These are often a final thought in the specification process, but by starting with the “brains” at the heart of any system, we can ensure it not only works properly from day one, but continues functioning efficiently throughout its working life.
What do you want the system to be able to do? Do you want time clocks to automatically switch on/off the heating and cooling so that you only use energy when the building is occupied? Do you want the air-conditioning to communicate with the BMES so that it’s not competing with other energy- consuming systems? How much control do you want people to have over their individual rooms? Do you want to limit the upper and lower temperatures to fixed set-points? How much monitoring and analysis do you want to do?
When listed like this, most of these questions seem obvious, but it amazes me how often these things are an afterthought.
Modern controls can be as simple or as advanced as you like. There are systems that let you monitor remotely, so one central point can plan, monitor and alter energy use throughout a single building or an entire network. These can control anything from one systems to up to 2000 units and offer the building owner complete control over all of the factors that affect energy use.
Starting the specification process by examining the control needed for any system will allow you to look at ways of minimising this energy use and that has to be good for everyone…
Philip Ord is product marketing manager for Mitsubishi Electric.
Source
Building Sustainable Design
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