The Ultimate Guide To Know About Chiller Plant

July 22, 2022

Industrial Water Chiller systems are used in many applications where cooled water or liquid is circulated through process equipment. Water chillers, commonly used to cool products and machinery, are used in many applications. Among them are injection molding, tool and die cutting, food and beverage, chemicals, lasers, machine tools, semiconductors, and other technologies

An industrial chiller's job is to transfer heat from one area to another. Water or a water/glycol solution is commonly used to transfer heat to and from the Chiller Machine. This may necessitate the process chiller having a reservoir and pumping system. Ensure enough cooling is crucial to productivity and cost savings regardless of your sector or process.

What Exactly Is A Chiller?
How Does a Chiller Work?
What Are The Different Types of Chiller Systems?
Water-Cooled Chillers:
Air-Cooled Chillers:
Actions to Improve Chiller System Efficiency
How To Select The Best Chiller For Your Application?
Conclusion

What Exactly Is A Chiller?

A chiller is a machine that uses vapor-compression, adsorption refrigeration, or absorption refrigeration cycles to remove heat from a liquid coolant. The liquid could then be sent through a heat exchanger to cool equipment or another process stream (such as air or process water). Refrigeration generates waste heat, which must be vented to the atmosphere or, for greater efficiency, collected for heating purposes. Compressors used in vapor compression chillers can be of several types.

Today's most prevalent are the hermetic scrolls, semi-hermetic screws, and centrifugal compressors. The chiller’s condensing side can be either air or water cooled. Even though the chiller is liquid-cooled, it is frequently cooled by an induced or forced draught cooling tower. To Chiller Function, absorption and adsorption chillers require a heat source.

How Does a Chiller Work?

A Chiller System operates on the vapor compression or vapor absorption concept. Chillers deliver a steady stream of coolant to the cold side of a process water system at a temperature of around 50°F (10°C). The coolant is then pushed through the process, extracting heat from one region of a facility (e.g., machinery, process equipment, etc.) as it returns to the process water system's return side.

A chiller is a mechanical refrigeration system that uses vapor compression and connects to the process water system via an evaporator. The evaporator, compressor, condenser, and expansion mechanism of a chiller circulate refrigerant. Each of the above chiller components undergoes a thermodynamic process. The evaporator acts as a heat exchanger, transferring heat acquired by the process coolant flow to the refrigerant. The refrigerant evaporates, transforming from a low-pressure liquid to vapor as the heat transfer occurs, while the temperature of the process coolant decreases.

The refrigerant is then directed to a compressor, which serves numerous functions. First, it removes refrigerant from the evaporator and ensures that the evaporator pressure is low enough to absorb heat at the proper pace. Second, it increases the pressure in the evaporating refrigerant to ensure that the temperature remains high enough to release heat when it reaches the condenser. At the condenser, the refrigerant returns to a liquid condition. A cooling medium removes the latent heat released by the refrigerant when it transitions from vapor to liquid (air or water).

What Are The Different Types of Chiller Systems?

As previously stated, two separate cooling mediums (air or water) can aid in the transfer of the latent heat released as the refrigerant transitions from vapor to liquid. As a result, chillers can use two types of condensers: air-cooled and water-cooled.

Air-cooled condensers are similar to the "radiators" that keep automotive engines cool. A motorized blower is used to drive air across a grid of refrigerant lines. Air-cooled condensers require 95°F (35°C) or lower ambient temperatures to work well unless expressly constructed for high-ambient circumstances.

Water-cooled condensers perform the same purpose as air-cooled condensers, but the heat transfer takes two steps. First, heat is transferred from refrigerant vapor to condenser water. The warm condenser water is then piped to a cooling tower, where the process heat is eventually released into the atmosphere.

Water-Cooled Chillers

Diagram of Water-Cooled Chiller

A water-cooled condenser is linked to a cooling tower in water-cooled chillers. They are usually utilized for medium and large installations with adequate water supply. Because of their relative independence from swings in ambient temperature, water-cooled chillers can provide more consistent performance for commercial and industrial air conditioning. Water-cooled chillers range in size from small 20-ton versions to thousands-of-ton devices that cool the world's most extensive facilities such as airports, retail malls, and other structures.

A conventional water-cooled chiller condenses the refrigerant by recirculating condenser water from a cooling tower. A Water Chiller contains a refrigerant that is temperature dependent on the entering condenser water (and flow rate) and functions in proportion to the ambient wet-bulb temperature. Because the wet-bulb temperature is always lower than the dry-bulb temperature, the refrigerant condensing temperature (and pressure) in a water-cooled chiller. This can frequently function at a lower temperature (and pressure) than in an air-cooled chiller. As a result, water-cooled chillers can run more efficiently.

Water-cooled chillers are typically housed indoors, away from the weather. As a result, water-cooled chillers have a longer lifespan. For bigger systems, water-cooled chillers are often the only alternative. The water-cooled chiller is often known as Wine Chiller as people use it to store wines. The other cooling tower system will necessitate more installation and maintenance costs than air-cooled chillers.

Air-Cooled Chillers

Diagram of Air-Cooled Chiller

Air-cooled chillers rely on a condenser that is cooled by the ambient air. As a result, air-cooled chillers may find widespread use in smaller or medium-sized systems with limited space. In cases when water is a rare resource, an Air-Cooled Chiller System may be the most feasible option.

Propeller fans or mechanical refrigeration cycles are commonly used in air-cooled chillers to draw ambient air over a finned coil to condense the refrigerant. The condensation of refrigerant vapor in the air-cooled condenser allows heat to be transferred to the atmosphere.

Air-cooled chillers have the substantial advantage of being less expensive to install. Because they are less complicated than water-cooled chillers, they require less maintenance. Air-cooled chillers take up less area but are primarily found outdoors of buildings. As a result, the exterior elements will shorten their functional lives.

Air-cooled chillers' all-inclusive design minimizes maintenance expenses. Their relative simplicity and decreased space needs result in significant advantages in a wide range of installations.

Actions to Improve Chiller System Efficiency

Chiller costs account for a significant portion of your building's utility expenditures. What steps should be taken to save energy by maximizing the efficiency of the chiller system? Let's look at some options.

Ongoing Maintenance

Through adequate continuing maintenance, chiller systems will work more efficiently. Most businesses recognize the importance of this and have taken steps to include it into their day-to-day facilities management best practices. The following are some commonly recommended practices for chiller systems:

Condenser coils should be inspected and cleaned. Heat transmission significantly impacts chiller systems and is critical to producing effective chiller performance. Condenser coils should be checked for blockage and unrestricted airflow during routine maintenance.

Keep the refrigerant charge constant. A chiller's cooling quotient depends on correct refrigerant levels in the system. Maintaining the proper refrigerant charge can significantly influence energy efficiency by lowering cooling costs by 5-10%.

Cooling tower condenser water loops must maintain proper water flow as intended. The condenser water loop can be harmed by debris such as sand, erosive substances, and contaminated chemicals. Fouling or scaling can obstruct water flow and reduce chiller efficiency significantly.

Predictive Maintenance

Artificial intelligence (AI) is becoming more prevalent in everyday practical applications. AI algorithms will improve machinery such as chiller systems by detecting possible breakdowns before they occur. Predictive maintenance uses the gathering and analysis of operating data from chiller systems to determine when maintenance activities should be conducted before catastrophic failure. Because chiller systems are at the heart of most modern HVAC systems, preventing catastrophic breakdowns that cause considerable "downtime" saves on emergency repair costs and reputation. The important role of a chiller system justifies the increased scrutiny. Big Data and AI will reduce downtime and increase productivity.

The Internet of Things (IoT) serves as a data collection tool, allowing AI applications such as predictive maintenance to be realized. In reality, AI and IoT are the future of HVAC. IoT allows for collecting real-time data from a chiller to conduct continuous analysis of its operation. The granular IoT data collected from a chiller will far exceed what can be obtained from visual inspection. The Internet of Things gives building engineers real-time visibility of essential HVAC assets, allowing for intelligent monitoring of actual operational conditions.

Optimization

Chillers are part of a complicated HVAC system. Water-cooled chillers are more complex since they are linked to a cooling tower system. To evaluate the entire chiller plant performance, consider the total power consumption of the compressor, pumps, cooling tower fans, and so on. They will be analyzed to assess comprehensive efficiency metrics such as kW/ton.

The optimization of the entire chiller plant must be done holistically. Adjustments are needed on ideal chilled water set points, chiller sequencing, and load balancing, peak demand management, cooling tower water management, and so on. They are only possible with operational data. IoT can give the means for such optimization by monitoring power consumption from each component of the chiller plant in real-time. They are supply/return temperatures from the chiller and cooling tower, water flow rates from the condenser water loop, and so on. HVAC has found a practical application for IoT to provide actual optimization.

How To Select The Best Chiller For Your Application?

Selecting the best chiller can be daunting sometimes. However, we’ve enlisted some of the steps you must follow to determine about chiller if it is best for you:

Step 1: Determine The Heat Load

It is critical to assess the heat load of your application to guarantee that the chiller selected is large enough for the intended use.

There are numerous methods for estimating heat load (in kW), but understanding the process is critical for obtaining an appropriate heat load.

Step 2: Determine The Temperature, Coolant Type, and Flow Rate

When the heat load is determined, the coolant, its target temperature, and the flow rate the chiller must give to the process are determined. The mechanism by which heat is transported from the process to the coolant and the type of coolant utilized determine this. For instance, water and oil have different characteristics.

Step 3: Identify Installation Environment

What environment will the Chiller Plant be installed in? Indoor applications, for example, may endure high temperatures and unclean environments, while outdoor installations may encounter both low and high ambient temperatures. This can impact chiller sizing and necessitate the use of accessories such as air filters, sump warmers, and so on.

Step 4: Use Chiller Performance Curves

Based on the chilled water supply temperature and the highest projected ambient air temperature, utilize the chiller performance curves. As it gives a chiller model that meets or exceeds the required capacity. To maximize the value of the chiller selection, consider the application's safety margin with available frame sizes.

Step 5: Check Pump Performance Curves

Request and review the pump performance curves to ensure that the pump will deliver enough pressure at the design flow rate to meet the application's requirements. Some liquid-cooled systems have short coolant flow pathways or extensive lengths with higher-than-average pressure losses.

Step 6: Final Selection

Finally, ensure that the selected standard chiller meets the remaining application criteria, such as power characteristics, control options, footprint, agency listing, color, etc. Choosing a standard chiller means improved dependability, easier service with common spare parts, and global support.

Conclusion

So, we have mentioned all about Chillers. However, in conclusion, the operational efficiency of your chiller will have a significant impact on your building's operating costs. From the standpoint of facility management, ongoing routine maintenance is the bare minimum. Real-time operational data is required for predictive maintenance and optimization of the chiller system. IoT has enabled new types of chiller efficiency.