Showing a measure of control

Measuring a building’s HVAC system performance is the only way to improve energy efficiency over its lifespan. But does the current economic situation drive project capital cost cutting at the expense of longer term operational cost saving? Jonathan Jones of Pentair Thermal Management explains.

In new build or renovation projects, budgets have never been tighter. Yet, what we expect from our asset’s performance has never been higher – and rightly so. We need to ensure that the building management system (BMS) is effective for a start and that it’s HVAC systems, which are invariably from a plethora of manufacturers, are able to feedback into the BMS with quality data to help enhance systems, post occupancy, for long term cost and energy saving. But here’s the rub; the inevitable squeeze on capex often means a removal of system functionality crucial to energy optimisation.

System specification is the first step to delivering tangible long term energy efficiency and return on capital investment. Ensuring that a building’s current needs are met whilst being flexible enough to allow expansion or upgrade at a later date, is an absolute must. But delivering such flexibility has a cost. When costs come under scrutiny, this is often the area of compromise.

Control and monitoring

If we take a single pipe DHWS as an example. The initial specification of a single pipe hot water distribution system from centralised plant is generally accepted to be the low energy consuming method for getting hot water from A to B, rather than recirculating via a secondary return system. It makes sense of course as the energy loss from a single pipe is obviously less than that from a flow and return pipe. But it is the control and monitoring of such a system which will give the most advantageous result over time.

Yet stresses on capex budgets often mean that the monitoring element of control and monitoring is dropped to trim costs. Losing the ability to monitor system performance longer term is a serious disadvantage to the building services manager. Whilst a control system will ensure hot water arrives at the tap, it is the monitoring features that will ensure it has been achieved in an efficient way. Moreover, if it has not been achieved efficiently, then there is useful information for remedial activities.

Scalability is also important over the lifespan of an asset. Consider a hospital. It is often the case that sections of the building are brought online over a period of time. Therefore, systems including control and monitoring solutions need to be scalable. As a result, offering a reduced cost solution which meets the needs of the building today may in fact be a diseconomy in the longer term.

Communication should also be made as simple as possible and available in open BMS language protocols to avoid compatibility issues. Open communication protocols such as BACnet, Lonworks, and KNX ensure that independently controlled systems can be brought together within the BMS.

The importance of training

Training for system commissioning and on-going facilities management should be as much part of the product as the physical device. Such training for system maximisation and energy efficiency will ensure that the building services manager or building owner will get the maximum from the total system. From commissioning to maintenance and system support, the facility manager must be able to lean on the manufacturer for support. System specification, installation training and best practice, commissioning, post occupancy system optimisation, maintenance guidance and services must be available to ensure cost effective running of the asset over its useful life.

The ACS-30 Control & Monitoring product from Pentair provides complete system performance and energy consumption data, for all heat tracing systems within the building. The scalable system allows for modular growth of systems as a building evolves or usage change occurs. Its open communication via BACnet, Lonworks MetaSys, and KNX protocols allows connection to BMS solutions, with training and installation, commissioning, operation, and maintenance services available from Pentair.

The message is actually simple; a little extra investment in capex can often ensure longer term savings in opex and often future capex. Therefore, a long term total expenditure (Totex) saving to the building owner is to be expected or even demanded. When it comes to building assets I paraphrase the old adage, “The bitterness of poor energy performance remains long after the sweetness of low price is forgotten.”

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