FMs must note rapidly changing legislation and take measurement of energy efficiency on board when specifying climate control systems, says Daikin UK's Graham Wright.
2 November 2015 | By Graham Wright
In a case of less carrot, more stick the Government has been quick to reinforce the stick in the form of building regulations and remove the carrot in the form of incentives, schemes and initiatives.
However, there is a fear within the industry that the building regulations will stagnate after a recent announcement that they won't be amended or changed until 2020.
The 2013 changes to Part L of the building regulations and the various clean air ventilation requirements, building tightness specifications, and fire resistant duct work, although welcome, will be the last changes the industry is likely to see to the regulations, possibly stunting the environmental and sustainable progress the sector has made.
The Government also recently scrapped the zero carbon homes initiative and the green deal and reduced solar and wind subsidies causing uncertainty about its commitment to reducing CO2 emissions in the UK. With this in mind, building owners and facilities managers need to understand the future energy demands of their buildings, along with legislative changes, before specifying and procuring air conditioning systems. They need to ensure that the right equipment is used to help buildings achieve their energy reduction targets.
For example, when designing new buildings or undertaking refurbishment work, many organisations use BREEAM as a mandatory standard to ensure that they meet the requirements for CO2 emission reductions. BREEAM uses approved techniques of measurement to assess energy efficiency. A typical BREEAM assessment will assess factors including, but not limited to, the management of a building, best practice commissioning, water usage, the life-cycle of the construction materials used, surface water run-off and the effect of the building on the ecology around a site. Credits are accumulated throughout the build, or refurbishment, to give a final BREEAM rating. The most credits are awarded for good energy management including the specification of climate control systems, so it makes good financial sense for building owners to invest primarily in air conditioning before looking at lesser-weighted options.
Other considerations
If BREEAM is the first consideration for building and facilities managers, the next is the Energy Efficiency Ratio (EER), used to describe the heating and cooling efficiency of air conditioners. It is measured by assessing the ratio of heating or cooling provided by a unit relative to the amount of electrical input required to generate it. Thus, if an air conditioner generates 5kW of cooling from a 1kW electrical input, its EER is said to be 5.0. The higher the EER, the more energy efficient the equipment.
Much like EER, seasonal energy efficiency ratings (SEER) are a way of measuring the true energy efficiency of heating and cooling technology, but over an entire cooling or heating season. The performance of the equipment is measured across different climate zones, at partial and full capacity, in auxiliary and stand-by modes and over different load requirements across the seasons. The lower the rating, the better - and, it's a realistic measurement that brings us nearer to closing the performance gap.
Seasonal effects
For facilities managers, the SEER rating results in significant savings: from the improved data and the resulting product development. Innovations such as variable refrigerant temperature have led to increases in seasonal efficiency of up to 25 per cent; with newer systems offering flexibility to achieve top efficiency throughout the year, balanced with a quick reaction speed on the hottest day or at peak loads.
However, sizing the plant correctly to enable facilities managers to get the most out of their climate control system is crucial as even with the right EER and SEER calculations, incorrectly sized equipment can be detrimental to a building's energy targets. Building use, the size of the building serviced and its occupant levels will often point towards the required plant size.
Only accurate specification can ensure that the system strikes a balance between performance and cost. Under-specification can lead to a mismatch in required and actual cooling/heating outputs, while an over-specified plant may result in increased operating cost and prevent the climate control system from achieving its maximum efficiency.
To achieve this, variable refrigerant volume (VRV) systems sizing software are used to deliver advanced modelling capability for heat recovery VRV systems. It runs thermal dynamic simulations and calculates annual loads, power inputs and efficiencies, which can be used as system efficiencies for Part L to meet regulatory requirements, with automatic sizing of the VRV system and correct selection of indoor and outdoor units.
In order for building and facilities managers to meet energy targets and ensure correct specification and sizing of equipment, it is vital that air conditioning contractors are engaged at the earliest opportunity. FMs with knowledge of legislation and energy efficiency measurements and who have the right level of support from manufacturers and distributors, can ensure the correct equipment is installed and that they are maximising the opportunity to reduce energy usage in their buildings in line with government requirements.
Graham Wright is a legislation expert at Daikin UK