By upgrading condensate recovery systems, healthcare estates managers ‘can make major energy savings and reduce their carbon emissions’, according to steam system specialist, Spirax Sarco.
The company said: “In fact, by returning condensate to raise boiler feed water temperature by 6°C, you can achieve a fuel saving of 1%. Next to steam, condensate is the most valuable resource available to any steam system operator. While almost every energy centre is likely to have some kind of condensate recovery system in place, the financial benefits of upgrading the system are too good to miss. In short, it makes economic sense to ensure that every last drop of condensate is recovered.”
Spirax Sarco says it has come to such conclusions ‘because condensate not only contains up to a quarter of the total energy of the steam from which it came, but is also valuable as a source of treated water ready for the boiler’. The firm added: “Every litre of condensate recovered and re-used is one litre less of fresh, cold water that needs to be treated and heated into steam. The more condensate returned to the boiler, the lower the fuel, water, and water treatment chemical bills. Most hospital steam systems could be achieving a condensate recovery rate of 75-80%.”
Four key areas Spirax Sarco suggests should be focused on are:
• Steam trap surveys: ‘A good start point is to commission a professional steam trap survey to identify where gains could be made. Such a survey will also give an estimate of the potential financial benefits through upgrades – helping to justify maintenance expenditure’.
• Condensate pumping: After leaving the steam trap, the condensate may need to be pumped back to the boiler house for re-use. Condensate pumps may be electrically powered, or mechanical, which are usually more efficient, because they use the steam itself for motive power. Once again, professional advice can be sought on the most suitable pumping technology for a specific system.
• Efficient feedtank systems: Having extracted the condensate from the steam system and sent it to the boiler house, it then needs to be mixed with the existing water in the boiler feed tank. This is most efficiently achieved by a deaerator head that mixes returned condensate, flash steam, and cold make-up water as they are fed into the feedwater tank. It is well worth ensuring that returned condensate is fed back into the boiler as efficiently as possible.
• Recovering flash steam: ‘Substantial energy savings can also be gained by installing flash steam recovery systems’. Flash steam is released from hot condensate when its pressure is reduced, typically when steam traps discharge condensate, or when water is removed from the boiler during blowdown. Recovered flash steam can be used for heating in its own right, and every kilogram of flash steam used in this way is a kilogram of live steam which does not need to be supplied by the boiler.
Spirax Sarco concludes: “Condensate recovery upgrades in all four of these areas can be very cost-effective, achieving a payback of between one and two years, with some measures paying for themselves in as little as weeks.”
