The GXV
supplies mains hot water, removes the need for a cold water storage tank and pipework run
in loft spaces. The primary
pump, three-port valve, cylinder thermostat, domestic blending valve, and wiring centre
are securely factory fitted and wired, making site installation very simple. No sealed
system controls on cylinder since it is vented and no domestic water is stored. Removes the
need to balance the boiler flow. Installer
only needs to connect to the boiler, radiators, feed & expansion tank, and mains
supply. Controls
centralised and easy to access for servicing.Adaptable
Designed
to operate with virtually any vented gas boiler. Removes the
need to balance the boiler flow. Small unit
dimensions, only 850mm tall, allows installation in small cupboards or under worktops. High hot
water flow rates, up to 30 litres/minute, permitting supply to multiple outlets. Large volumes
of hot water, up to 170 litres @ 43°C, suitable for use in larger houses. High hot
water pressures, for mains supply up to 6 bar, for use in multi-storey constructions.New products for water conservation
Fast
delivery of hot water to taps reduces water loss while waiting for the supply to reach a
usable temperature. High pressure
supply allows use of smaller bore hot water pipework, further reducing the volume of water
drawn off until the supply reaches a usable temperature. Very Rapid
recovery avoids water waste because a bath is not hot enough to use.Innovative energy efficient hot water supply & space heating
Control
of boiler return temperatures allows maximum efficiency to be gained from condensing
boilers. Boiler made to operate in condensing mode as long as possible during heat-up. Significantly
reduces boiler cycling. CFC Free
Insulation locks away stored heat. Low storage
volume, 80 litres, reduces standing heat losses. Domestic
plate heat exchanger designed to be self-cleaning at typical supply flow rates.Assuredly safe electrical/gas equipment installations
Fully
vented primary system and storage cylinder. Primary
system controls factory fitted and wired to high quality standards. Fused wiring
centre. Simple step
by step installation procedure helps prevent mistakes. The small size of the unit, typically 80 litres, ensures rapid recovery from a standard boiler. Following a bath, a 12kW (40,000 Btu) boiler can recover the entire store within 20 minutes.
The greatest problem that faced us when designing the GXV was obtaining the large volumes of hot water that were demanded from such a small unit. After a year of experimenting with various systems, we developed a way to extract nearly 100% of the stored heat, and at the same time ensure that 100% of the boiler output went directly to the taps. This combination of stored heat and boiler input finally allowed us to fill a bath at 25 litres per minute to 43°C, with surplus stored heat left in the store. In factory tests the GXV provided 170 litres at 45°C, and at an average flow rate of 25 litres per minute.
The methods we use to achieve this also provide hot water within 3 minutes of cold start.
Energy Efficiency: One big advantage of the method used to recover the stored water, is the ability of the GXV to automatically control the return temperature to the boiler. To achieve the maximum efficiency from a condensing boiler the return to the boiler must be kept below 55°C. The GXV will hold the return to the boiler at a pre-set temperature, typically 53°C, until the entire store has been heated to this temperature. During this recovery, the boiler will be continually in condensing mode and will not cycle.
Energy efficiency is further increased as a result of the small capacity of the unit. With such a small surface area heat losses are minimised. CFC free factory foam insulation, combined with pipe insulation, keeps stored heat locked away.
Water and heat waste is reduced by the extremely fast response times to taps. When a tap is opened, the hot water supply temperature jumps nearly instantaneously to the set output temperature on the thermostatic blending valve, so that the user does not have to run off water waiting for the temperature to climb to a suitable level. The fact that the water is at mains pressures also enable the use of small bore pipework, further reducing water waste.
To reduce energy loss through central heating, the units make use of a programmable room thermostat that provides accurate control of room temperatures, allowing different temperatures to be set for different times.
Reliability: Any hot water or heating system is only as reliable as its individual components. That is why we have made sure that every component used in the GXV has been tried and tested to work in the field. All assembled pipework is made to the highest standard using high quality fittings and jointing compounds to ensure leak free commissioning. The cylinders themselves contain primary water, and so are protected against scale. A corrosion / scale inhibitor may be added to the store to provide added protection to the complete system.
Easy to Install: At an early stage in the design process, it was realised that the easiest way to ensure correct rapid installation of all system controls is to supply the installer with a fully pre-fabricated system. Any system components that have to be fitted by the installer, because they cannot be pre-fabricated, should be simple to connect, requiring the minimum of additional on-site work. With all components factory fitted, wired, and tested, specifiers could then rest easy in the knowledge that the hot water and heating systems in properties fitted with a GXV had been put together exactly as required.
In addition to the Heat Bank Thermal Store controls, the GXV Heat Bank Thermal Store is factory fitted with all the usual domestic hot water and heating system controls, including Domestic Blending Valve, Primary Circulating Pump, Motorised Three Port Valve, Cylinder Thermostat, Wiring Centre. The only part of the control system that cannot be factory wired is the room thermostat. We were able to overcome this by using a Danfoss TP5E RF room thermostat and RX1 digital radio receiver. The room thermostat communicates with the receiver, fitted and wired to the Heat Bank Thermal Store, using a digital radio signal. The room thermostat runs for two years of two standard AA batteries, requires absolutely no wiring, and can be easy positioned (or re-positioned) to suit.
System Balancing: The way that the GXV unit operates removes the need for a balancing valve between the boiler and the store.
System Adjustment: All system components are factory pre-set to work with a typical domestic central heating installation. The only controls that may need adjusting are the domestic blending valve - to take account of the users personal preferences regarding the hot water supply temperature - and the room thermostat – to suit the users requirements.
Easy to maintain: One of the greatest problems that service engineers face is the inaccessibility of controls, preventing them from being easily serviced. We have therefore made it a high priority, in designing the GXV unit, to position all components where a service engineer can be certain to reach them. Full maintenance instructions, including such information as the system wiring diagram and fault finding chart, will be supplied with each unit. Bosses, pipes, and controls are clearly labelled to assist with the installation of external pipework conections.
GXV Demonstration: During a demonstration conducted using a GXV Heat Bank Thermal Store in conjunction with the Vaillant VU186EH condensing boiler, the following procedure was followed, and readings taken:
1. The boiler was fired and left to fully heat up the stored water.
2. The hot water outlet into the bath was fully opened.
3. 120 litres was drawn at an average of 50°C and an average flow rate of 25 litres per minute.
4. Without pause, a further 50 litres was drawn, to make a total of 170 litres of water at 45°C.
5. The hot water outlet was closed and the system left for only 3 minutes to recover.
6. The hot water outlet into the bath was then opened again.
7. A further 15 litres of 45°C water was drawn – sufficient for a basin or sink.
8. The hot water outlet was closed and the GXV Heat Bank Thermal Store left for 23 minutes to recover.
9. The hot water outlet into the bath was again opened.
10. A further 160 litres at 45°C was drawn off.
11. The entire test was then repeated with very similar results.
Solar Applications: It should also be noted, that a solar version of the GXV has also been developed. The small storage size required with a GXV unit for domestic use make it ideal for solar applications. A typical 250 litre domestic solar cylinder requires the gas boiler to heat up around 115 litres of water for domestic use, leaving 130 litres dedicated to solar heating. A similar sized GXV unit, requiring only 80 litres for domestic use, would provide 170 litres for solar use. This additional solar storage increases the gains from solar panels and the energy efficiency of the entire system.