Simple method to improve Chiller efficiency and reduce power consumption.

Chillers consume more than 50 percent of the electrical usage in many facilities. They use approximately 20 percent of the total electrical power generated in INDIA, and it is estimates that chillers expend up to 30 percent in additional energy through inefficiency. With more than 100,000 chillers in INDIA alone, inefficiency costs industry billions of Rupees in energy annually.

Chillers running inefficiently also result in decreased equipment reliability, more frequent maintenance, and shortened lifespan. The slightest decrease in chiller performance can have a major impact on efficiency. For instance, every 1 deg F increase in condenser water temperature above full load design can decrease chiller efficiency by 1-2 percent. A failing or neglected water treatment program can reduce efficiency 10-35 percent, or more in extreme cases.

What is maximum chiller efficiency?
Contrary to popular belief, running the chiller at full load design and achieving the design Kw/ton does not necessarily mean the chiller is running at maximum efficiency. Maximum chiller efficiency is producing the greatest tonnage at the lowest kilowatt usage.

Maximum efficiency occurs with most chillers running at approximately 70-75 percent load and the lowest Entering Condenser Water Temperature (ECWT), based on design. Knowing a chiller’s efficiency and the effects of load and ECWT will help the facility determine the most efficient chiller configurations, saving the maximum on energy costs.

Document chiller data
The first step in maximizing chiller efficiency is to establish a method for recording chiller operational data in a daily log. It is common for facilities to maintain chiller logs, but unfortunately they rarely get reviewed, which is critical.

The daily logs can be entered into a chiller efficiency program. If past chiller logs exist, the data can be input and a baseline can be immediately established. Once the chiller status (baseline) has been determined, operational changes can be made to increase efficiency and measure the results.

Alternatively a sophisticated Chiller performance analyser CLIMACHECK be used to document the performance of Chiller. This can be rented from Greenwave , Vadodara. E mail ; geev@greenwavecapital.com

Ensure accurate data
Ensuring accurate data can be difficult. One of the most common assumptions made by a facility is that the flow to the chiller is constant and always at design. Unfortunately, this may not be the case and there are several reasons why. Chiller systems are dynamic, ever-changing models, which must adapt to the environment around them. They expand and contract from the original design. They are subject to wear, tear, and age. The best advice is to not assume anything until proven by accurate, continuous verification.

The best way to provide precise data, obtain concrete results, and minimize problems is to verify flow rates to the chiller for tonnage measurements and other calculations to determine efficiency. Four methods for determining flow are inline flow meter, external flow meter, delta pressure, and delta temperature.

Flow meters—turbine type, magmeter (inline), or ultrasonic (external)—provide the most accurate flow readings in gallons per min (gpm). Flow can be determined by delta pressure using a gauge or annubar or with CLIMACHECK analyser. Delta temperature cannot actually measure the flow rate in gpm, but it can identify proper flow and problems associated with flow. It also can be affected by other conditions not directly related to flow, such as a scaled or fouled chiller barrel, non condensable gasses, and refrigerant level, making interpretation more difficult. However, the use of delta temperature along with a flow meter or delta pressure gauge creates a powerful diagnostic tool that can detect problems affecting efficiency in the chiller system.

Along with proper flow, check and calibrate sensors, gauges, and meters for measuring temperature, pressure, and electrical measurements periodically or when a problem is detected.

Maintain refrigerant levels and OIL FOULING.
The ability of a chiller to efficiently remove heat directly correlates to the compressor’s ability to move the refrigerant per unit of time. It is important to maintain proper refrigerant levels because low levels cause the compressor to work harder and less efficiently . Check for leaks regularly, especially when a chiller shows signs of low refrigerant level. Trending refrigerant levels will help determine if the chiller has a leak(s), a bad purge unit, or refrigerant carryover.

It is recommended to use PERMAFROST refrigerant Oil Additive in the heat exchangers so that any OIL FOULING that has taken place is removed for once and all to get back original cooling efficiency.

Regular refrigerant analysis is an important part of determining chiller inefficiencies. If oil content in the refrigerant is above the chiller manufacturer’s guidelines, it may be reducing heat transfer. Keeping good maintenance records on oil usage and treating it with PERMAFROST Refrigerant Oil Additive in a chiller will help to avoid this condition.