Exploiting the benefits of direct-gas-fired water heating

David Pepper
A solution for most requirements – David Pepper on direct-gas-fired water heaters.
DAVID PEPPER examines the issues solved by considering direct-gas-fired water heaters.Many factors need to be considered in the selection of domestic-hot-water equipment, whether for new build or refurbishment project. Each application will have its own particular requirements, but careful thought needs to be given to achieve the right balance for an effective and efficient water-heating system which will give value for money as well as meeting the customer’s needs. In most applications, direct-gas-fired water heaters have many benefits and can provide a solution for most requirements. Reliability Possibly the most obvious but crucial consideration is reliability of supply. From a commercial perspective, an inadequate supply of hot water for a hotel or restaurant can be extremely damaging for business. This is equally so in manufacturing, where unplanned down time will always cause disruption and loss of revenue. Even more problematic would be loss of supply in buildings such as schools, hospitals and prisons. There could be nothing worse for a head teacher or senior manager in the NHS being faced with closing down a school or hospital because of problems with the hot-water supply. Faster response Direct-gas-fired water heaters can provide a much faster response than electric or indirect systems. This means storage can be reduced, saving on space and also standing losses in addition to minimising the potential for legionella colonisation. The next subject for consideration is the type of demand for hot water. It can be split into three main categories. The first is continuous demand, such as an industrial process. Second is intermittent peak in places such as hotels or schools. Last is short heavy peaks such as occurs in sports clubs and leisure centres. There is a wide variety of gas-fired products which can cater for all types of demand. Cost will always be a major consideration. The generation of hot water can be a significant proportion of total energy usage in buildings as previously mentioned, therefore the efficiency issues must be properly evaluated. Direct-gas-fired water heaters eliminate the heat-transfer losses and part-load inefficiencies, which occur with traditional indirect systems. Quality Ultimately, equipment quality should be high on the list, and sustainability and longevity issues are increasingly important as end users place greater emphasis on life-cycle cost. When seeking equipment which is going to last, copper-fin gas-fired-water heaters offer many benefits, as they provide natural resistance to corrosion caused by electrolytic action which can occur in soft water areas and their design allows scale-free operation in hard-water areas. Scale-free operation gives an added bonus of being able to maintain high levels of efficiency throughout the life of the equipment. Even a very thin layer of scale will cause a significant reduction in efficiency on traditional indirect systems and also gas-fired storage-type units. In addition to maintaining high efficiencies, copper-fin units also last longer. A contingency or back-up system is essential when selecting equipment for hospitals or hotels and highly desirable for many other establishments where a failure would be a major inconvenience. Dual installations are commonplace, but alternative-fuel standby may also be worth considering. Copper-fin units are supplied with a ‘buffer’ storage cylinder and these are available with the facility for electrical immersion heating to provide hot water in the event of gas-supply problems. In many cases, space availability and ease of installation is a common requirement. most engineers would agree plant room space is often very limited, particularly with refurbishment projects on both old and more modern buildings. Therefore physical dimensions and weight of equipment are very important, and a system which will meet hot-water demands of the building, but also fit into a restricted space is highly desirable. Direct gas-fired water heaters are compact in design and construction. There are many options available, including balanced-flued models which provide even more installation flexibility. Answer As with many building-services requirements, there is never one product or system to suit all requirements. However, with careful planning and real consideration of the factors discussed, a modern direct-gas-fired water heater will usually provide the answer. Where natural gas is not available, propane can offer many advantages over other fuels. In properties such as restaurants and hotels, propane-fired water heaters can reduce total energy running costs, particularly if the establishment is already using propane for catering equipment. Water-heater manufacturers have a wealth of knowledge and expertise available, so specifiers and those responsible for product and system selection would be well advised to seek their help from the outset. David Pepper is managing director of Lochinvar Ltd, Lombard Way, The MXL Centre, Banbury, Oxon OX16 4TJ.
Related links:
Related articles:



modbs tv logo

New Sustainability Director for Wates Group

Wates Group, a family-owned development, building and property maintenance company, has appointed Cressida Curtis as its new Group Sustainability Director.

Domus Ventilation appoints new contractor sales managers

Ventilation systems manufacturer Domus Ventilation has announced the arrival of three new Contractor Sales Managers.