TRUE or FALSE? When full load is not required, it’s best to shut down units in multiple chiller plants

As there are many myths in the industry, and they can remain in people’s minds. Daikin Applied UK are committed to putting our expertise and knowledge at the service of the people to clear up any misbeliefs. We aim to bring value and help customers make informed decisions when working on commercial heating, cooling and ventilation (HVAC) projects.  This is why we have created a series of the most common myths in the industry and are going to be MYTH BUSTING.

Amongst the myths in the HVAC industry, there seems to be is a lot of information out there about the use of multiple chiller plants and how to manage them effectively. When it comes to large buildings, chiller plants may have a number of different units installed working together to reach the target cooling capacity needed to satisfy the cooling needs for that building.

While multiple chiller plants can achieve high cooling capacity targets more easily, energy efficiency must still be considered. Energy efficiency impacts the environmental friendliness of the building as well as the operating costs that building owners have to bear.

It is often thought that the best way to run a multiple chiller plant is to shut down part of the units when there is no requirement for full load, instead of running all of the units in part loads.

In the instance of multiple chiller installation, many consider shutting down chillers (and the related pumps) as the load decreases, as this is thought to be the best way to achieve maximum energy efficiency when full load is not required.

 

Is this TRUE or FALSE?

 

Well, the answer is false.

Thanks to the high efficiency in part load operation with inverter, running all the chillers in the plant in part load (even if they have “fix-speed” pumps on primary circuits) can be more efficient than shutting down part of the chillers.

The Inverter or VDF (Variable Frequency Drive) is an electronic power component, by varying the frequency of the motor power supply; it modulates the compressor rotational speed (RPM) and in such a way that is controls the compressor capacity.

 

Read more here about the benefits of using inverter technology

 

This technology is recognised in being responsible in helping chillers and heat pumps deliver great efficiency performances, especially when it comes to part load efficiency.

This technology can become crucial also for multiple chillers applications, not only ensuring greater energy efficiency levels and lower operating costs, but also lower maintenance costs and quick Return on the Investment (ROI).

 

Click here to find out more about why part load efficiency is important

 

Here is an example!

In the hospitality industry, specifically in a hotel, the load typically varies depending on the season or room requirement. During the pandemic for example, hotels could not operate at full capacity.

 

Click here find out more about HVAC systems for hotels

 

Let’s look at a specific hotel application. A hotel requires 2MW of cooling capacity at 46° C design ambient conditions. Considering that the multiple chiller plant (Fix speed pump on Primary plant) would run 8,760 hours per year and the cost of electricity would be 0.11 €/kW, here is how Inverter chillers would compare to non-Inverter chillers.

 

Location Seasonal efficiency Savings on operating costs ROI
Dubai 24% higher 24,220 EUR/year 13 months

 

Relying on controls to sequence the chillers in the plant

 

When a HVAC project requires the load across multiple different sized units to be split, it may be useful to rely on smart solutions that can help control the chillers as if they were one big single unit.

The Daikin Intelligent Chiller Manager (iCM), for instance, is a smart tool that can be used to help achieve such a solution. It is a tool designed to control, sequence and optimise the performance of multiple chillers, and is the perfect solution for this type of plant application. The iCM, in fact, harmonises the way every single chiller in the plant operates, this allows them to reach their goal with minimum effort for energy consumption. This positively impacts the chillers’ durability and efficiency.

 

Are you working on a project requiring a highly efficient multiple chiller plant? Then, get in touch with the form below!

 

 

 

 

 

 

 

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