Library collections require close temperature and humidity control with the ability to cope with fresh air and constant heat loads.
According to the National Library of Australia, the humidity in libraries should be limited to below 50 per cent relative to avoid mould problems with books.
Temperature is important also as most moulds thrive at warmer temperatures. Temperatures below freezing will not kill mould, but they do make it dormant. For patron comfort, temperatures of 210C, plus or minus two, are acceptable in libraries, provided relative humidity is kept at 50 per cent.
To avoid massive energy waste by continually overcooling and reheating the entire air stream, a dedicated outside air system (DOAS) should be considered. To save energy with DOAS the supply air humidity needs to be below 6.50C dew point (6g/kg) and around 200C, otherwise the internal latent heat from people and outside infiltration is excessive: i.e. 230C at 50 per cent RH gives 8.8g/kg. A 70W or 100g/h latent heat per person requires 3.08g/kg drier, based on the ventilation rate of 7.5l/s per person.
Gordon Lacey of Air and Aqua Tech, uses his original DOAS moisture depression check to show potential clients the efficiency of using desiccant dehumidifiers and compare them to other systems on offer
This system requirement is best achieved with 16,000l/s of commercial desiccant dehumidifier.
At another leading Australian University the library, along with its consultancy firm AECOM, chose a Seibu Giken DST desiccant dehumidifier after an exhaustive selection process.
The Seibu Giken Econosorb configuration utilises chilled water, refrigeration to make waste heat plus evaporator capacity with a Seibu Giken desiccant rotor for free performance with waste condenser heat.
The desiccant DOAS design is established in the USA, Asia and Australia for green buildings, supermarkets, hospitals, museums and other indoor environments needing humidity control and energy savings.
Seibu Giken DST are a Japanese energy and desiccant technology company and a leading innovator inventing the silica gel wheel rotor now used by all of todays desiccant dehumidifier manufacturers.
Seibu Giken stands for western (Japan) research and technology and reflects the personal philosophy of its founder, Toshimi Kuma: “ideas can only emanate from accumulation of knowledge”.
Air and Aqua Tech support this technology locally, headed by Gordon Lacey with 25 years desiccant system experience.
According to Lacey the desiccant dehumidification market has doubled in Australia over the last few years and potential buyers are showing more focus on energy savings rather than first cost, “designers are now understanding that dehumidification is an expectation rather than a premium,” he says.
The technology lends itself to the growth in green buildings world-wide and public facilities coping with large people movement such as museums and galleries.
Gordon Lacey: 1300 002 228.