How to save energy on existing chillers
Energy conservation in factories is one of the major challenges facing all managers. In particular, cooling equipment is under heavy load in the summer when temperatures rise, and many people are concerned about power consumption of chillers.
Upgrading to the latest, more efficient equipment is an easy way to save energy, but it comes at a high cost and is not realistic if your existing chiller still has a significant lifespan remaining.
This time, we will introduce how to reduce power consumption of existing chillers by setting and adjusting them, without having to replace the equipment.
1. Chiller power consumption can be reduced in various ways
If you want to reduce power consumption of your chiller, many people may first consider switching to an inverter type with high power-saving capacity or the latest energy-saving equipment.
However, this requires high costs and effort, and the chiller cannot be used during replacement, which affects the operation of peripheral equipment.If the existing chiller still has some life left, try what you can do now rather than rushing to update the equipment.
cooling capacity of a chiller can be made more efficient by adjusting the temperature settings and flow rate at circulating water inlet and outlet. The first step to saving energy is to carefully review the settings to ensure they are not wasteful in relation to the usage environment.
In the next chapter, we will introduce in detail three ways to make chillers more energy efficient.
- - Change the set temperature of circulating water
- ・Adjust the flow rate
- ・Introduce a control system
2. [Method 1] Change the set temperature of circulating water
The smaller the temperature difference between the inlet and outlet of circulating water, the better the chiller's performance (COP). Therefore, checking the required temperature based on usage conditions and resetting the settings to minimize the temperature difference is an effective way to save energy.
The energy saving measures document from the Energy Saving Support Subcommittee of the Great East Japan Earthquake Investigation Support Headquarters states that changing circulating water outlet temperature setting from 5-7°C to 9-10°C can be expected to reduce electricity consumption by 6-8%.
However, changing the chiller temperature setting cannot be done unless you have an accurate understanding of the control capacity under load and light load. Keep in mind that in some cases the manufacturer may need to be present.
3. [Method 2] Flow rate adjustment
Adjusting the flow rate of circulating water is also an effective way to save energy in chillers.
The initial flow rate setting is generally set to a value that is larger than the actual required amount, assuming peak times. Resetting the flow rate to a lower value that matches the actual situation reduces the load on the pump power, leading to energy savings.
In addition, an inappropriate flow rate setting can also cause unnecessary load. If the actual circulation flow rate is higher than the set value, the chiller will be overloaded, not be able to obtain sufficient cooling capacity, and consume more electricity than necessary.
If you notice anything unusual about the chiller's cooling capacity or power consumption, you may be able to improve the situation by rechecking and adjusting the flow rate settings and reviewing the temperature profile, such as the outlet temperature of the heat source unit.
4. Regular maintenance is the basis for energy conservation
As you can see, there are several ways to make chillers more energy efficient, but the most basic method is regular maintenance.
Accumulated dirt and worn-out parts reduce heat exchange efficiency and overall performance, resulting in unnecessary power consumption. Regularly inspections and clean the fins, piping, and heat exchanger, and also overhaul them depending on the operating hours.
inspections and maintenance of chillers is required by law to prevent leakage of fluorocarbons, but in addition to preventing accidents, it also has other major benefits, such as extending the service life and reducing running costs.
Updating equipment requires a great deal of effort and high investment costs, but frequent inspections will extend the life of existing chillers and reduce overall costs in the long term.
５．まとめ
There are various ways to reduce power consumption of existing chillers. Adjusting the inlet and outlet temperatures and flow rate of circulating water to suit usage conditions is an effective way to save energy on chillers, but if changing the settings is difficult, consider installing a control system.
However, the basis for saving energy with chillers is maintenance. Accumulated dirt and worn-out parts result in unnecessary power consumption and shorten the equipment's lifespan. Keeping the equipment in good condition through regular inspections is the best way to save energy, which also leads to reduced overall running costs.
