Which chiller system is best?

Many regions around the globe continue to face significant water scarcity issues. Efforts to desalinate and trade water are clear indicators of the severity of this concern. According to the World Bank, two billion people currently experience absolute water scarcity, a figure that could rise to 4.6 billion within the next 65 years. The interplay between water and energy has become an important subject in recent times. Power plants, which fuel most countries, consume vast amounts of water, either directly or indirectly. When conducting a feasibility study for a cooling plant, the decision to use water or not is critical. Based on the results, one would choose between water-cooled or air-cooled chillers.

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Understanding Chillers

A chiller is essential for removing heat from a load and releasing it into the environment via a refrigeration system. These heat transfer devices are prevalent in power plants and other large-scale facilities. Simply put, it’s a system composed of a reservoir with ethylene + water or water alone, along with circulation components. Coolant circulates from the reservoir through the equipment being cooled. In addition to water-cooled chillers, there are air-cooled chillers that utilize fans to disperse heat. These have become increasingly common in industrial settings. This article will cover the differences between these two types of chillers to help you make an informed choice, with the support of ARANER.

Water-Cooled Chillers

Water-cooled chiller systems include a cooling tower, making them generally more efficient than air-cooled options. This efficiency arises because water-cooled chillers use the ambient temperature bulb temperature, which is typically lower than the ambient dry bulb temperature. The lower the chiller’s condensing temperature, the more efficient it is. Key components of these systems include:

• Cooling towers
• Condenser water pumps
• Make-up water pumps
• Chillers
• TES reservoirs

The advantages of water-cooled chillers include their smaller footprint compared to air-cooled versions, higher efficiency, and longer lifespan. They are particularly suitable for indoor installations.

The Role of the Evaporator

The evaporator in a water-cooled chiller generates chilled water, which is then circulated throughout the facility. Released at approximately 6°C (42.8°F), this chilled water is pushed by a pump through a network of pipes. After absorbing heat from the building, the water temperature increases to about 12°C (53.6°F) and returns to the evaporator for cooling again.

The Function of the Condenser

The condenser in this system removes unwanted heat from the evaporator. Once the refrigerant passes through the condenser, a loop involving the cooling tower facilitates further heat removal. The condenser water enters at around 27°C (80.6°F) and exits at about 32°C (89.6°F), moving to the cooling tower. Notably, the refrigerant and condenser water never make direct contact; heat exchange only occurs through a pipe wall.

The Cooling Towers

This is where the unwanted heat from a facility is ultimately discharged. A large fan supplies air to the cooling tower, which then interacts with the condenser water. This interaction allows the condenser water to lose heat to the air, cooling it down before it is recirculated. Various designs such as cross flow, counter flow, natural draft, and mechanical draft are available for cooling towers, each suited to different conditions.

Air-Cooled Chillers

In settings where aesthetics, environmental conditions, or water access are restrictive, air-cooled chillers are a viable alternative. While both air-cooled and water-cooled systems use an air stream for heat transfer, air-cooled chillers rely on ambient air alone. These chillers are generally perceived as less expensive and highly efficient, although they have a significant advantage in not consuming water. ARANER has leveraged modern manufacturing techniques to create highly effective and efficient air-cooled chillers, which are competitive in terms of footprint, efficiency, and noise. Despite misconceptions about their efficiency, modern air-cooled chillers have shown progressive improvements in NPLV (non-standard part load value) ratings. In part-load applications, these chillers are particularly reliable. Benefits include:

• No need for cooling towers
• Better environmental stability without water wastage
• Lower maintenance costs
• Ease of operation and control
• No chemical or water costs
• No water-related issues in case of a disaster

Fig 1: Air-Cooled Chilled Alongside Water Cooled (Traditional) Chiller

Deciding Between the Two

Cooling capacity is a crucial factor when choosing between these chillers, and equally important is the balance between operating costs and capital costs. Some clients focus mainly on initial costs, but a comprehensive value-based analysis that considers both factors is advisable. For water-cooled chillers, remember to factor in the cooling tower costs. Evaluating the life cycle cost involves both purchase and operating expenses. When looking solely at first costs and water costs, water-cooled chillers may appear more valuable. However, a thorough assessment gives a more accurate picture.

Exploring Hybrid Chillers

Hybrid chillers can operate as air-cooled or water-cooled depending on conditions, making them suitable for areas with dry climates or inconsistent water availability.

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Main Advantages of Water-Cooled and Air-Cooled Chillers

Energy cost is a major consideration in any powered equipment. While water-cooled chillers may be more energy-efficient, air-cooled chillers offer advantages in installation cost, maintenance, and the number of required components. They also eliminate water consumption, making them ideal for water-scarce areas or places with cheap energy but high water costs. Ready to make your choice? Contact us for specialized and customized assistance. If you enjoyed this post, you might also want to explore different heat rejection condensing technologies.

What Type of Chiller is Best? - Drake Refrigeration, Inc.

There are many types of chillers, each with unique configurations and capabilities. Determining the best chiller largely depends on factors such as:

• Your budget
• Your application and environment
• Your preferences

Best Chillers for Year-Round Operation

For industries requiring all-season performance like medical, dairy, food processing, and manufacturing, industrial process chillers are ideal. Unlike standard comfort chillers that may face issues in winter, industrial-grade chillers operate efficiently year-round.

Best Chillers for Tight Temperature Control

Many industrial applications have strict temperature requirements. In these cases, industrial process chillers with variable frequency drives (VFDs) and recirculation tanks are optimal, maintaining temperature control to within +/- 1°F.

Best Chillers for Minimum Installation Costs

For budget-conscious projects, packaged air-cooled chillers are quick to install and involve fewer components, saving on upfront costs.

Best Chillers for Energy Efficiency

Energy efficiency is increasingly crucial for cost-saving and resource conservation. Both air-cooled and water-cooled chillers offer energy-efficient features, making it essential to consult with a seasoned expert.

Best Chillers for Limited Interior Space

Packaged air-cooled chillers are perfect for environments with limited indoor space, as they are housed outdoors and do not require additional square footage for cooling towers or condenser pumps.

Best Chillers for Longevity

Packaged water-cooled chillers, which are kept indoors, are protected from harsh outdoor elements, extending their lifespan compared to outdoor air-cooled units.

Best Chillers for Water-Sensitive Environments

In areas prone to drought or with limited water access, air-cooled chillers are the best option as they use ambient air instead of water to cool processes.

Best Chillers for Low-Temperature Requirements

For industries with intense chilling needs, such as aerospace, food processing, and ice rink operation, low-temp chillers are optimal. These units come with oil management systems to keep fluids ultra-cool.

Best Chillers for Noise-Sensitive Environments

Water-cooled chillers are ideal for hospitals and other noise-sensitive areas, as they use quiet-flowing water instead of sound-producing cooling fans.

Best Chillers for Humid Environments

In humid settings, air-cooled chillers are preferable as water-cooled versions might exacerbate moisture levels.

Best Chillers for Non-Compatible Packaged Units

If your environment lacks continuous water sources and has poor ventilation, a split system chiller with separate outdoor and indoor sections is the best option.

Whether your chiller needs match these scenarios or require something else entirely, we invite you to partner with us. We customize our robust engineered solutions to satisfy any requirement. We back up our products with exceptional after-the-sale support and a 2 door vertical chiller uptime rate. Reach out to our team online or call (888) 289-7299 to discover the best chillers for you.