High value in smart gas valve choice
Commercial buildings are being forced to be ever more energy efficient, but all too often the humble gas valve is forgotten when it comes to new build specification or as a retrofit. Paul Aston explains how being ahead of the game on gas valve choice could ensure increased energy efficiency in commercial buildings
THE PRESSURE TO deliver ever more energy efficient buildings is relentless for architects, specifiers and constructors working on new build or renovation projects, but also for facilities and building managers running the building once completed.
The seemingly inexorable increase in energy costs is fuelling the search for solutions.
Nowadays, high efficiency boilers, low energy lighting and high efficiency circulator pumps are the rule rather than the exception.
Attention is increasingly turning therefore, to new or previously overlooked areas of the building, which consume energy and offer, via more accurate specification or retrofit, the potential for cost savings once the building becomes operational.
The gas valve is one such area. Often given little thought by the architect or specifier and overlooked by the facilities manager, the gas valve can offer considerable savings on running costs and mitigate a building's environmental impact.
However, it is not only specifiers, architects and facilities managers who have overlooked the gas valve. BREEAM assessments, the world's foremost environmental assessment method and rating system for buildings, which has assessed more than 250,000 buildings across the world takes into account a variety of building products to reach a rating for an individual building. Everything from internal blinds, through to heating controls, solar panels and water metering all contribute towards the assessment, but gas valves are rarely mentioned.
I suspect one of the reasons is that the gas valve is a fairly inconspicuous part of a gas piping system. Pipes are more noticeable to the aesthetics of the building, playing a vital role in transporting liquids and gas around a system. However, pipes only transport the gas and cannot regulate the flow or switch it off completely in the event of an emergency or as part of a routine maintenance programme. This is the role of the gas valve.
Gas valves are a permanent feature of all commercial buildings, from libraries and factories, through to hospitals and schools, ensuring safety through controlling the flow of gaseous media and shutting down the gas supply in emergency situations.
There are two types of gas valve that work in different ways, solenoid valves and electro-hydraulic valves. Both types of valve differ significantly in terms of how they operate, but also have significantly different impact, in terms of energy usage and its knock-on effect on building running costs and also carbon emissions.
Solenoid valves work by using mains electricity to generate a controlled magnetic field which affects the state of the valve and lifts a plunger to open or close the valve door. With this type of gas valve, energy input is required 24 hours a day, seven days a week in order to maintain the magnetic field as the valve door moves between the open and closed position.
Electro-hydraulic valves are very different. This type of gas valve works by using electricity to activate a pump and apply pressure onto a piston. When this pressure reaches a certain point a micro switch is triggered which locks the hydraulic fluid into the piston and enables the valve to stay in the fixed position. With an electro-hydraulic valve, high energy input is not required 24/7 which means there is considerable scope for a reduction in building running costs.
However, despite the potential for energy savings, the solenoid valve remains, at the present time, market leader. This is due to the fact that solenoid valves have a lower initial purchase cost. However, as building running costs increasingly come into focus, it is my belief that facilities managers will increasingly need to take account the whole life cost of the valve, particularly when considering replacement or retrofit.
The constant energy use involved with the running of a solenoid valve unsurprisingly results in high electrical power and carbon consumption rates. A typical solenoid valve consumes 0.0892Kg carbon per hour, 24 hours a day, 365 days a year. This equates to £387 per year with an annual carbon usage of 781kg.
In comparison, electrohydraulic valves, such as the Alcon HWA, consumes 0.014KW of electricity per hour and has an overall carbon usage of 64.33kg annually. This EN161 approved electrohydraulic valve costs £31.80 per year which means that a building can achieve a payback period of less than 18 months compared to a typical solenoid valve. This can result in valuable reductions in energy and carbon usage for buildings, such as schools, care homes, hospitals, residential tower blocks and commercial kitchens.
Specifiers and facilities managers are too often in the dark on the potential for power consumption savings. Savings from less obvious sources, such as the gas valve, can help to ensure a building is more energy efficient, but all-too-often this vital piece of equipment is overlooked.
It is my belief that with greater recognition of the ongoing running costs of gas valves and a focus on whole life costs rather than just initial purchase cost, the electro-hydraulic valve is about to come into its own and could deliver real savings on building running costs.
My advice to specifiers, architects and facilities managers is to take a closer look at the humble gas valve when considering the efficiency of a building. All too often the specification of a gas valve is a tick-box exercise with no real thought given to alternative products. For facilities managers, the replacement of a solenoid valve with an electrohydraulic version is a relatively easy process with short payback periods and clearly identifiable costs savings.
// The author is an expert in the use of gas valves in building service applications at Xylem Flow Control UK //
22 January 2014