A guide to temperature control efficiencies:
INTRODUCTION
As becoming more energy efficient is at the forefront of the world’s priorities for a greener future, the UK industrial landscape is evolving to adapt to this more sustainable way of living. It is therefore essential for end-users to carry out a full energy analysis of their equipment in order to assess which areas they can upgrade with more efficient solutions. Additionally, with new models constantly being developed along with flexible payback periods being introduced, users are now in a better position to invest.
We’re here to talk you through just a few of the top ways you can lower your power usage, significantly save on long-term bills and boost your energy efficiency by upgrading your operating systems.
FREE COOLING (STAND ALONE AND INTEGRATED)
Living in Britain, it probably won’t come as much of a surprise to you that the average UK monthly temperature sits below 15 degrees for eight months of the year… but it turns out that our mild climate works in our favour when it comes to saving energy. Enter what we call ‘free cooling’ – a concept which utilises ambient air to reduce the energy consumed by a cooling circuit and the electrical power load of the entire system.
The good news is you can easily adjust your current cooling system to achieve further savings, resulting in a far more feasible alternative to most of the cooling required. For example, if your operating system is above 10 degrees, you can raise the temperature by an extra 1 degree – making for a more efficient design that is closer to the ambient air temperature – without hindering the operation itself.
When it comes to investing in free cooling, organisational budgets can present a challenge for industrial end-users but with many offering an 18-24 month pay-back period, cooling systems are becoming more accessible than ever before. Plus, since they last an average of seven years, integrating free cooling into an industrial system in some form can contribute to five or more years of highly valuable savings.
So, now we have covered the basics of free cooling, let’s break down the two ways it can be achieved – both of which can provide multiple benefits:
- Standalone Free Cooling
Whilst standalone units have a larger surface area and therefore take up more space, they can provide up to 70% savings on running costs every year. Now that’s impressive! The bigger size enables better part loading for the air to circulate around the units, allowing for 100% free cooling at a higher ambient air temperature than integrated cooling chillers.
- Integrated Free Cooling
Ideal for sites that don’t have the capacity for standalone units, integrated free cooling is compatible with systems that have a capacity of 100kW and above. Therefore, if you’re managing a multi-megawatt project but lacking extra floorspace, this solution would be particularly fitting for your needs as it is more compact but just as powerful.
HEAT RECOVERY
Recycling waste heat from the hot discharge refrigerant is another resourceful option for those looking to make more efficient savings on their process temperature control equipment. This highly useful method enables the energy to be used in other heated or HVAC processes, from pre-heating to prewarming for a boiler.
That being said, it is certainly a good idea to invest in equipment that has cheat recovery capabilities – which can help to increase overall energy efficiency. Retrofitting an existing chiller could also be considered as a second solution that can boost efficiency, providing the condition of the plant allows for it. If you do choose this solution, the starting point is around 250kW.
The great eco benefit from using heat recovery modification is that it reduces the energy required for the cooling process. And with the lower usage of heat load to cool and effectively result in a reduction of boiler costs, running a full load is no longer necessary. Not only that, but since less heat is being used, working conditions are improved – resulting in a happier, healthier workforce.
COMPONENT SELECTION (NEW PROJECTS AND RETROFIT UPGRADES)
CHILLER COMPONENTS
Of all the temperature control equipment available, chillers are known for requiring the most energy to run. With two ‘halves’ (low pressure and high pressure) they can run more efficiently if these sides are closer together. The quality of the chiller, however, is highly important for boosting the efficiency of a unit whilst in use. Therefore, with that in mind, let’s look at the key components to consider when purchasing a chiller…
- PUMPS
Pumps are the most energy-intensive component of the chiller, and all cooling towers for that matter. It’s therefore crucial to ensure the chiller has variable dials that enable you to choose the speed setting depending on your capacity – unlike straight forward on/off pumps. This reduces power wastage, whilst contributing to savings of up to 50% on pump energy.
- HEAT EXCHANGER (SHELL & TUBE)
Perfect for process end-users, shell and tube heat exchangers tend to be just as affordable as brazed plate heat exchangers, but provide higher efficiency and have more capacity for operators that use higher temperatures. Heat exchanges come with a variety of ‘passes’, which indicate how many times the fluid is required to go through the exchange before it reaches the necessary temperature. Opting for one with several rather than a single pass is the more energy efficient choice – but be sure to check it is compatible with your specific model.
- COMPRESSORS
Another component that requires a greater amount of energy to run a chiller is the compressor. With the demand for eco-friendly equipment being higher than ever, upgraded versions have been developed to ensure any new installations and upgrades run more efficiently. These can offer significant energy savings of up to 60% compared to standard models – plus temperature adjustments as small as -3 degrees between screw and turbocor compressors can contribute to a staggering 56% in energy savings.
- CONDENSERS
Despite not being able to decrease energy usage, micro-channel condensers are highly effective in reducing the amount of refrigerant required – and ultimately helping to save costs and make the chiller run more economically. They are also essential when it comes to ensuring the equipment is compliant with the latest requirements of the F-Gas legislation.
- ELECTRONIC EXPANSION VALVES
Electronic Expansion Valves (EEVs) have proved to be considerably more efficient than standard options, thanks to their ability to operate on a lower pressure ratio without hindering the chiller’s functionality. They can also contribute to a 12% energy saving every year and can be easily retrofitted – more than making up for the initial investment required to install them. In fact, payback can be achieved in just 12 months.
- EC FANS
Electronically Commutated fans use a DC motor as opposed to a traditional AC motor – enabling greater efficiency and lower noise levels. Capital expenditure wise, they are higher, but the quick payback period makes up for the saving benefits they can provide. In addition, if you chose to add a variable speed control in replacement of a standard on/off fan control, a further energy savings of up to 14% can be made every year.
PIPEWORK AND DUCTING
Given its ability to increase long-term energy savings, pipework is a brilliant resource for boosting efficiency. To avoid risk of diversions in buildings, the pipework system needs to be short in length and well insulated, as this will help to trap the heat in and reduce energy wastage.
MAINTENANCE
Being proactive in maintaining your chiller is essential for ensuring it runs to its highest performance, whilst operating at maximum potential efficiency over the long-term. This is where Planned Preventative Maintenance Programs come in to their own – enabling industrial managers to keep on top maintenance checks keep on top of maintenance effectively.
When it comes to chillers, both a constructive water treatment program and carrying out frequent water system checks is crucial to ensuring that all components are functioning as they should. This also reduces the risk of contamination and avoids unnecessary energy being used overall.
Condensers have a tendency to become blocked – particularly in spaces with higher dust – so simple tasks such as regular cleaning of the installation can help to boost efficiency.
The power input of the condenser becomes lower when the condensing temperature goes down, which can have a negative impact on the efficiency. This is a good example of how regular maintenance checks can prevent the risk of wastage from happening and, thankfully, it’s an incredibly simple job to do.
It’s also worth noting to end-users that reducing a chiller’s temperature by a mere 1 degree can result in the saving of an impressive 4% in overall energy usage – a small but mighty improvement on yearly financial savings.
REFRIGERANT TYPE
Becoming more energy efficient can be both easy and low maintenance for end-users and opting for a low GWP refrigerant is a great example of this. Despite smaller, standard chillers not having the capabilities to achieve similar results to more eco-friendly refrigerants, new models have been produced that are able to tackle these challenges, resulting in lower operating costs and improved system efficiency.
These more recent refrigerants include screw compressors, which use non-flammable R513A and have a far lower GWP value in comparison to the R134A. Further benefits of these newer models include cooling temperatures as low as -8 degrees and being compatible with ammonia – as well as being the top refrigerants for medium pressure applications.
As manufacturers migrate away from HFC’s, the choice of refrigerants for end-users is better than ever before – allowing them to consider models on the basis of their efficiency, as well as the industry and application.
POWER FACTOR CORRECTION
Power factor correction is a crucial aspect for industrial end-users to consider when moving to a more energy efficient operating system. This is essentially a way of measuring the electric power to determine how effective it is before being converted into useful output. The standard power factor correction is 0.95 for most industrial sites, which can be set on switchboards.
When it comes to chillers, the average power of compressor efficiencies sits at around 0.86 – but with the right efficiencies in place it is possible to lower this even further to 0.81. This can be achieved by specifically targeting parts with lower power factors and adjusting them accordingly, resulting in lower power bills and ongoing energy usage.
GET IN TOUCH!
Want to learn more about the ways we can help your organisation run more efficiently, improve profitability and work towards a greener future? Get in touch today!