Save quick, but don’t get in a fix

Sabien, dry cycling, boiler, Quick fixes
Effective quick fixes — Tony Willis

The ‘quick’ in ‘quick-fix’ energy-saving projects should apply to the savings and the payback, not the decision-making process, says Tony Willis.

Increasing gas prices, legislation and carbon taxes are adding to the pressures businesses and public sector organisations face to reduce their energy consumption. As a result, the already-popular ‘quick fix’ or retrofit solution is set to become even more popular.

By their very nature, quick fixes tend to address the low-hanging fruit — typically areas of building-services systems that are currently wasting energy and can quickly be improved. In most cases, the ‘quick’ also applies to the payback period, as this will impact on the viability of many such projects — at least in the financial director’s view. Such low-hanging fruit can encompass all areas of the building’s operation and, very often, how they are controlled. Lighting left on when it is not needed, ventilating unoccupied areas and firing boilers when there is no demand for heat are all commonly encountered examples of energy wastage.

Whatever the particular area to be addressed, our experience of delivering many energy-saving retrofit projects for commercial boilers is that there are certain key considerations that should be applied in most cases.

The first thing, of course, is to identify the cause of the wastage. Are the boilers sequenced correctly, has weather compensation been deployed, has the BMS been recently optimised or upgraded? Or are the boilers firing to compensate for their own standing heat losses— rather than in response to a true demand for heat from the building?

The next stage is to determine whether there is a sensible and effective solution to the wastage that has been identified. Then it is necessary to investigate the market to see what solutions are available. In the current energy-conscious times there is no shortage of such solutions, but I would certainly urge a ‘buyer-beware’ approach. Unfortunately, many such solutions are based on unproven theories, or they may be technologies that have failed in the past but been reincarnated with a new look backed by new spiel.

Consequently, thorough evaluation of any technologies under consideration is a must. Does the claimed method of operation actually make sense in engineering terms? Has the technology been proven through independent testing in other projects in the field? Will the manufacturer encourage you to talk to other users to gain the benefit of their experience?

Also, can the product be easily retrofitted to existing systems without disrupting current settings? This is a major concern for building-services engineers as there have been examples of retrofit control technologies causing problems with existing control strategies. These include early attempts to control boiler dry cycling that would suppress firing by changing the boiler’s designed set point, or basing firing patterns on historical activity rather than actual demand.

Sabien, dry cycling, boiler, Quick fixes
Eliminating boiler dry cycling and its associated waste of energy is an effective retrofit technology that does not compete with the operation of a heating system.

So any chosen quick-fix technology needs to work in harmony with the existing systems, rather than in competition with them. For example, when addressing boiler dry cycling , any such technology should integrate with existing building-management systems or weather compensation — and definitely should not alter set points.

There may also be situations where the end client wants to be able to evaluate the success of a quick-fix project, calculate the actual payback and see if it delivers the predicted return on investment. So it is important that appropriate ways of measuring energy consumption before and after are in place. And in the case of any heating systems, degree-day analysis must be used to allow for changes in ambient temperature. The supplier should be able to help with this if necessary.

Another major consideration relates to the practicality of installation and commissioning of the technology. It is all very well suggesting to an end user that such-and-such a technology be installed, but it is important that this can be done with minimum impact on internal resources and no impact on building operation.

To that end, the supplier of the retrofit technology should be able to help with this, managing the entire project and taking care of communications with each of the sites and all stakeholders. Again, talking to that supplier’s other users will give a good idea of their project-management capabilities.

Armed with this logical approach, it is possible to achieve significant energy savings for end clients, and deliver a sensible return on their investment. In the boiler-dry-cycling example, for instance, installation of an intelligent boiler load optimiser that satisfies all of the criteria above will typically reduce gas consumption by between 10% and 25%, with a payback of less than two years. And that is a very worthwhile quick fix.

Tony Willis is Technical Sales Director with Sabien Technology

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