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Perhaps the easiest way to save energy costs lies in the replacement of outdated heating and cooling equipment.
Buildings constructed 30 to 40 years ago are often still equipped with original fire tube hot water boilers. Boiler efficiency in this era was 70% or less under full load. Under part load, their efficiency drops to 65% or less. Replacement of these older, fire tube boilers with mid or high efficiency boilers provides the greatest single-purchase potential for energy savings and cost reductions.
Current boiler technology captures the majority of the combustion heat before the exhaust gas leaves the chimney. Modern boilers also have modulation controls to enable the boiler to work efficiently under part load.
The heating efficiency of a mid-efficiency boiler is roughly 85%, whether under full or part load. The cost savings in gas consumption are approximately 20%, which means recouping the cost of the new system inside the first ten years of operation.
A high-efficiency boiler, particularly one that is carefully integrated regarding return water temperature control (return water temperature must be kept below 50°C) will raise the heating peak efficiency to 95%. However, if the return water temperature falls below 50°C, the efficiency of this system falls below 90%. Reduction in gas consumption is 30%, which again pays for the unit in under five years; after which time, your energy costs are lowered for the life of the boiler.
Chillers from the same time period (30 to 40 years ago) are centrifugal units that have been improved with advanced technology to state-of-the art centrifugal units. Some older chillers are being replaced by new screw chiller technology. Replacing these older units drops energy consumption to half, saving building owners much in cooling costs. Additionally, the modern chillers reduce peak summer demand. Again, similar to the boiler replacement savings, new chillers essentially pay for themselves inside ten years.
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