It’s time to think about changing up your chiller
With MEES, ErP, EPC, Lot21 and F-Gas now a stark reality for building operators, 2018 may be the best time to look at upgrading your old chiller system. Jason Tinsley explains more.
This year sees a number of changes to building efficiency and energyrelated legislation that place a focus on building services and make 2018 the right time to consider updating equipment such as chillers.
There are already several well-established drivers aimed at encouraging energy efficiency in buildings, including Part L of the Building Regulations. But on 1st April 2018 the Minimum Energy Efficiency Standards (MEES) will be in place and these are set to put significant emphasis on the energy efficiency of buildings.
It’s not you, it’s MEES
MEES makes it illegal for commercial landlords to grant a tenancy if their property has an energy performance certificate (EPC) rating of F or G.
Figures show that around 20% of commercial properties fall nto the F or G ratings for EPCs, which amounts to around 200,000 commercial buildings.
CIBSE recommends that buildings with older EPCs should have the certificates updated, because since their introduction, the underlying calculations behind EPC ratings have been updated in several important ways, including baseline assumptions about the energy performance of building services equipment.
It is also safe to say that in many older buildings, information on the performance of building services can be difficult to locate. Information that was originally supplied by manufacturers may be lost, and in some cases is simply no longer available.
In the absence of such information, an EPC assessor will use standard assumptions about the energy efficiency of equipment such as boilers, fans and chillers which are likely to be lower than actual performance.
With these points in mind, 2018 is a good year to consider updating building services equipment. In the case of chillers, there are other factors which make new technologies an attractive and cost-effective option for the long-term.
F-Gas and R22
If a building incorporates chiller equipment, then it’s likely to be a large energy user, particularly if is five to ten years old.
There are two other important developments which make a chiller update a prudent business decision.
The first is the F Gas regulation, which came into force in 2015. Since that time, systems using R22 refrigerant could not be repaired or topped-up with that refrigerant because of its ozonedepleting potential.
R22 was a commonly-used refrigerant, so repair and maintenance of older chillers may be impossible to carry out at this point. Whilst it can be possible to use ‘replacement’ or ‘dropin’ refrigerants, these offer no guarantee of energy performance levels and are not a long-term response to the legislation.
It’s worth looking at chillers that use the low GWP (Global Warming Potential) refrigerants HFO 1234ze (GWP >1) and HFO 1234yf (GWP 4). HFO fluorinated molecules have a very low environmental impact, while retaining thermodynamic properties very similar to HFCs, guaranteeing high energy performance levels.
Second is the Energy related Products (ErP) legislation. The ErP is part of the Ecodesign regulation (EU) 2015/1188 and is a European policy aimed at improving the energy performance of all kinds of products used in businesses and homes.
Each product falls into a ‘Lot’ and the regulations are being introduced in stages. On 1st January 2018, Lot 21 was introduced and this includes comfort chillers and high temperature process chillers.
The main impact of the ErP Lot 21 is on the way that chiller efficiency is measured. Ratings will be based on higher requirements for seasonal efficiency, and many older existing chillers will simply not comply.
One of the most significant aspects of the ErP is that it requires measurement of the efficiencies to be carried out by manufacturers to agreed national and European standards. These standards are set out in the Official Journal of the European Union (OJEU), and they provide a ‘presumption of conformity with the Regulations.’
For comfort cooling chillers, the key figure that must be supplied by manufacturers is the seasonal space cooling energy efficiency. This figure will replace any other measures of efficiency or energy use that have previously been used under EU or UK regulations, so when selecting a new chiller, it is important to check this information.
The benefit to specifiers, installers and users is that when they look at a product which carries an ErP energy label, they will know that the measurement against the MEPS has been carried out in the same way by each manufacturer – making comparison of performance much easier and more robust.
Efficient chiller technologies
Air conditioning is acknowledged as a significant energy user. The latest chiller technologies address this by operating to meet the precise cooling demand of a building.
Inverter technology is key to this aspect of energy efficiency. For example, the latest e-series modular chiller uses two advanced DC inverter driven scroll compressors. This delivers a capacity range of 8% to 100%, ensuring that the chillers do not operate at full capacity when that is not required.
Not only does this reduce the energy costs of the chillers, it can also ensure longer operational lifetimes. Compared to a fixed speed or mechanically modulated compressor, an inverter compressor can reduce annual energy bills by up to 30%.
Manufacturers have driven down the energy usage of their products, and work hard to identify even small adjustments that can impact on efficiency. For example, one of the innovations in chiller technology is the use of U-shaped heat exchangers. These offer a greater surface area than the conventionally-shaped heat exchangers. An additional benefit is that the chillers are much narrower than conventional products, saving valuable floor space.
Another innovative approach is the use of a two-stage cooling circuit within a chiller. Two compressors are used in a single chiller unit, with each compressor serving a separate plate heat exchanger. By modulating the evaporating temperature individually, overall system efficiency can increase by an additional 3.9%, compared to single refrigeration circuit. By having two separate refrigerant circuits, it also allows the system to carry on operating in the unlikely event of a component failure within one of the circuits.
Today’s chillers can also be combined with other technologies, such as heat pumps by utilising some of the chillers waste heat, to offer another level of energy saving. For example, chiller technology teamed with a heat pump offers very high efficiencies, as well as introducing renewable elements to a cooling system that can help to meet local planning requirements such as the London Plan. Heat recovery is also an option, so that heat rejected from the building can be captured and used along with a heat pump to provide for the building’s sanitary hot water needs.
The latest chillers also offer both heating and cooling in a highly energy efficient way. For example, the Integra chillers offer a four-pipe product that offer heat recovery for simultaneous heating and cooling. This is a system that removes heat from one area of a building that requires cooling, and uses it to provide heating to other zones.
Heat recovery reduces energy consumption, and helps to cut building operating costs. In many projects, this type of chiller can remove the requirement for a boiler to provide heating, thereby also lowering capital expenditure.
Other practical benefits include a modular approach to chillers, which is available with modern inverter-driven technology. This can be useful for projects where plant space is at a premium, very low noise levels are required, or even sites where the building’s heating loads are expected to increase or decrease.
These modular options are generally available ‘off-the-shelf’ offering a quick solution that can be added to as required.
Time to consider the options
With legislation pushing buildings towards greater energy efficiency and new regulations bringing even more efficient chiller options to the market, specifiers have every reason to consider an upgrade.
In the UK 35% of building stock is commercial, so tackling energy use in these properties will make a significant impact to lowering carbon emissions. This is necessary because we have challenging targets for an 80% reduction in overall UK emissions by 2050, based on 1990 levels. Buildings contribute 30% of energy consumption and over 40% of greenhouse gas emissions, so there is an opportunity to make a difference regarding carbon reduction and energy efficiency.
Jason Tinsley is applied product marketing manager at Mitsubishi Electric.