HVAC SYSTEMS
n Compromised heat transfer. n Reduced cooling capacity. n Increased energy usage. n Damaged components. n Reduced energy efficiency. n Reduced longevity of the system.
A blocked coil; in the long run, Aermec says clogged coils will end up costing the plant’s user more.
access. The job is very labour-intensive, can be unpleasant, and requires a specific skillset to address safety issues and prevent any damage, particularly to the fins. However, you might ask: ‘Is cleaning coils really that important, and should you call in the experts?’ I would say the answer is ‘Absolutely’, since over time – if left – the surface of the coils will build up with contaminants and have an insulating effect, which will decrease the available surface area for heat transfer, and lead to excessive energy consumption and poor system performance, and shorten the life of your equipment. HVAC plant is a huge investment for any hospital, and year- round optimal performance is essential. Chillers draw in substantial amounts of air over the coils, which are at the point where the heat transfer takes place. Coils can all too easily become caked in assorted contaminants from dust particles, general dirt from the atmosphere, vegetation, and pollen. Salt-laden environments, meanwhile, add their own unique set of problems, including seagull droppings.
Equipment failure
Condenser coils are exposed to unfiltered air, and will accumulate debris and other contaminants at a predictable and consistent rate. When the coils get dirty, the compressors must work that much harder to produce the same amount of cooling, and clogged coils can cause many problems, including:
If left unchecked for substantial periods, with detritus allowed to build up, equipment could eventually fail, resulting in costly downtime. Dirty coils can also have a more human impact. Compromised cooling equipment can affect the general discomfort of a building’s occupants, resulting in lower levels of productivity, and could also compromise patient comfort. Despite knowing the positive benefits of coil cleaning, many are rarely cleaned, or cleaned poorly or irregularly, allowing contaminants to build, and in turn leading to corrosion and reduced coil life.
Frequency of cleaning
The frequency for cleaning coils varies according to environmental factors. In the UK, for example, cleaning is recommended after the pollen season is finished. Pollen fibres can quickly build up and become matted. Twice-yearly cleaning is recommended for most sites, and of course hospitals cannot afford any interruption or denigration of their facilities, and may require more frequent attention. Awareness of the coil’s environment and experience will help determine the right cleaning schedule. Although some companies have tried cleaning coils themselves to reduce maintenance costs, it is best left to the experts. The use of high-pressure washers, for example, can do more damage than good, as the excessive pressure can easily damage the coil, and lodge the dirt deeper within the tightly packed fins, making it more difficult to remove. Fluids incorrectly applied can also lead to corrosion and/or safety issues.
Optimal efficiency
Clean coils are essential to maintain optimal efficiency, and should be included as part of your overall asset management strategy. Many manufacturers can offer a variety of service and maintenance packages – including coil coating as an option – depending on the site and application. Don’t forget, however, to pay attention to other components. Upgrading condenser and air-handling unit (AHU) fans can achieve further efficiencies. Instead of buying new kit, upgrades can potentially save money and energy too. EC fans offer the same output as AC fans for less input, and consume 70% less energy. By installing EC fans, airflow is improved, and significant energy savings can be achieved.
The outer portion of a condenser coil, and a stark warning.
A site survey will identify the right programme for your plant, and recommend appropriate upgrades and/or
Paul Osborne
Paul Osborne’s experience in the HVAC industry spans some 30 years. He started his career in 1986, working on cold storage systems for agricultural applications, then moving on to customised refrigeration systems for the medical sector and the Ministry of Defence. He has unusually also worked on the design and build of bespoke refrigeration and Zero recovery systems used for fighter jets, a highly specialised area. In recent years he has applied his expertise to the commissioning and installation of chiller systems, and is now using his skills in his role as Service manager for Aermec UK.
October 2019 Health Estate Journal 127 ‘‘
If left unchecked for substantial periods, with
detritus allowed to build up, equipment could eventually fail, resulting in costly downtime
replacements to optimise performance. As with any mechanical system, it is important to follow the manufacturer’s recommendations for maintenance to ensure peak performance. Regular coil cleaning is important to promote longevity and high operating efficiencies. Unexpected repairs, downtimes, and higher maintenance bills, can be the direct result of not carrying out proper coil cleaning. Weighing up the costs and benefits of cleaning will enable you to work out a cost/benefit ratio for cleaning in the future, and keep the finance director happy. So, when was the last time coils were cleaned at your site?
hej
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92 |
Page 93 |
Page 94 |
Page 95 |
Page 96 |
Page 97 |
Page 98 |
Page 99 |
Page 100 |
Page 101 |
Page 102 |
Page 103 |
Page 104 |
Page 105 |
Page 106 |
Page 107 |
Page 108 |
Page 109 |
Page 110 |
Page 111 |
Page 112 |
Page 113 |
Page 114 |
Page 115 |
Page 116 |
Page 117 |
Page 118 |
Page 119 |
Page 120 |
Page 121 |
Page 122 |
Page 123 |
Page 124 |
Page 125 |
Page 126 |
Page 127 |
Page 128 |
Page 129 |
Page 130 |
Page 131 |
Page 132 |
Page 133 |
Page 134 |
Page 135 |
Page 136 |
Page 137 |
Page 138 |
Page 139 |
Page 140 |
Page 141 |
Page 142 |
Page 143 |
Page 144 |
Page 145 |
Page 146 |
Page 147 |
Page 148 |
Page 149 |
Page 150 |
Page 151 |
Page 152 |
Page 153 |
Page 154 |
Page 155 |
Page 156 |
Page 157 |
Page 158 |
Page 159 |
Page 160
