YORK Compression and Absorption Chiller Materials Application and Chemicals Limit Guide for Various Water Qualities

Important! Read before proceeding!

General safety guidelines

This equipment is a relatively complicated apparatus. During rigging, installation, operation, maintenance, or service, individuals may be exposed to certain components or conditions including, but not limited to: heavy objects, refrigerants, materials under pressure, rotating components, and both high and low voltage. Each of these items has the potential, if misused or handled incorrectly, to cause bodily injury or death. It is the obligation and responsibility of rigging, installation, and operating/service personnel to identify and recognize these inherent hazards, protect themselves, and proceed safely in completing their tasks. Failure to comply with any of these requirements could result in serious damage to the equipment and the property in which it is situated, as well as severe personal injury or death to themselves and people at the site.

This document is intended for use by owner-authorized rigging, installation, and operating/service personnel. It is expected that these individuals possess independent training that will enable them to perform their assigned tasks correctly and safely. It is essential that, before performing any task on this equipment, this individual shall have read and understood the on-product labels, this document and any referenced materials. This individual shall also be familiar with and comply with all applicable industry and governmental standards and regulations pertaining to the task in question.

SAFETY SYMBOLS

The following symbols are used in this document to alert the reader to specific situations:

• [DANGER] Indicates a possible hazardous situation which will result in death or serious injury if correct care is not taken.
• [CAUTION] Identifies a hazard which could lead to damage to the machine, damage to other equipment and environmental pollution if correct care is not taken or instructions and are not followed.
• [WARNING] Indicates a potentially hazardous situation which will result in possible injuries or damage to equipment if correct care is not taken.
• [NOTE] Highlights additional information useful to the technician in completing the work being performed correctly.

[WARNING] External wiring, unless specified as an optional connection in the manufacturer's product line, is not to be connected inside the control cabinet. Devices such as relays, switches, transducers and controls and any external wiring must not be installed inside the micro panel. All wiring must be in accordance with Johnson Controls published specifications and must be performed only by a qualified electrician. Johnson Controls will not be responsible for damage or problems resulting from incorrect connections to the controls or application of incorrect control signals. Failure to follow this warning will void the manufacturer's warranty and cause serious damage to property or personal injury.

Section 1 - Introduction

Water quality describes the chemical, physical and biological characteristics of water, with respect to its suitability for a particular purpose. As customers select lower quality sources for chiller water, such as treated sewage effluent (TSE) and sea water, selecting the appropriate materials of construction for the heat transfer equipment chiller material selection becomes even more critical. The purpose of this application guide is to define the requirements for compatibility of the water quality with the materials of construction. The recommendations in this guide assume that the customer will hire a qualified water treatment supplier.

Cooling system configurations

The typical design of a chiller has an evaporator (that removes heat from a building in a closed loop recirculating chilled water system) and a water-cooled condenser (that rejects heat to an open loop - a recirculating water system with an evaporative cooling tower). Like a mechanical chiller, a steam absorption unit has an evaporator and a condenser and closed and open cooling water systems; however, this system uses condensing steam instead of electricity to power the refrigeration cycle.

Condenser (open loop)

Spray nozzles on the top deck distributes water onto the plastic honeycombed fill to maximize the evaporation rate of water droplets. The cooling tower discharges a large volume of water into the atmosphere due to the heat of vaporization. Soluble contaminants cannot leave the tower with the vapor. Consequently, the concentration of these soluble contaminants in the recirculating water increases. The ratio of the concentration of a specific contaminant in the make-up (MU) water and the concentration of the same contaminant in the recirculating cooling water (CW) is called cycles of concentration (COC). Water treatment practitioners typically select silica as the contaminant to calculate the cycles of concentration.

COC = [contaminants] CW/[contaminants]MU

Make-up water

For each source of water, the specification limits for the make-up water in the tables define the worst case for water quality. In other words, the quality of the make-up water is so poor that the maximum cycles of concentration of the cooling tower is 1.5. 75% of the make-up water is lost by the combination of evaporation and blowdown. If the make-up water parameters are lower than the specification limits, the customer can operate their cooling tower at higher cycles of concentration, reducing the volume and cost of make-up water.

Recirculating cooling water

The specification limits for the concentrated cooling tower water in the tables assume that one or more of the parameters in the make-up water is at the maximum specification limit. This limitation results in a very low waterside efficiency of 1.5 COC. Most cooling towers operate at higher COC.

All evaporative, recirculating cooling water systems require a qualified water treatment professional to provide chemicals to protect the reliability of the heat transfer equipment. Unlike closed recirculating systems, engineers must select the materials of construction based on the qualities of the make-up and cycled-up recirculating cooling waters.

Evaporator (closed loop)

Typically, engineers should select the same materials of construction specified for the condenser. The customer's qualified water treatment professional designs the chemical treatment program to be compatible with the materials of construction of the evaporator closed loop system.

Water treatment fundamentals

The water treatment is to protect the heat transfer surfaces from corrosion, deposition, and fouling. Controlling corrosion, deposition, and bacteria-related fouling requires the continuous or intermittent feed of chemicals. There are two other sources of fouling: suspended contaminants in the make-up water and airborne contaminants entering the cooling tower. Cooling water with high concentrations of suspended contaminants is not compatible with enhanced tubes. Accumulation of foulants on enhanced tubes creates a risk of under-deposit corrosion that ultimately causes a perforation failure.

The most common technology to remove suspended contaminants from the cooling water is filtration of a portion of the recirculating cooling water (side-stream filtration).

How to use this guide

This document provides guidelines for water chemistry limits and material selection based on the following six categories of water quality used in heat transfer equipment:

• Potable water
• Non-potable water
• Low chloride TSE water
• High chloride TSE water, high TDS geothermal water, or high TDS well water
• Seawater
• Brackish water

You must reference this document first based on the water type being used as the heat transfer medium. You must reference the appropriate section which further defines the compatibility of various materials used in the construction of the equipment and the materials of construction.

Not all options for materials are available across all chiller products. For example, absorption type chillers typically use stainless steel tubes as a standard design requirement due to the nature of fluids circulating within the chiller system. It is important to note this during the selection of tube materials when specifying the chiller requirements.

Engineers should start their selection of materials by comparing the chemical analysis of the make-up water to the maximum limits of the key parameters in the appropriate table, paying special attention to the concentration of suspended solids and turbidity.

Next, determine whether the customer's site experiences high levels of airborne contaminants that increase the concentration of suspended solids in the recirculating cooling water. Sources of airborne contaminants include the following:

• Acrid or coastal environments
• Proximity to manufacturing plants that have airborne emissions
• Agricultural areas

Sites with high levels of airborne contaminants may require you to install filtration equipment.

If none of the categories of water quality conform to the specification limits of the key parameters of your make-up water, contact a water treatment expert for assistance.

Section 2 - Potable water quality specifications

The World Health Organization (WHO) has published international drinking water guidelines that have standardized the quality of potable water.

The following table defines the water quality specifications for potable water. Parameters marked with an asterisk are the most important make-up water parameters for compatibility with materials of construction. If the make-up water quality has one or more parameters that do not meet these specification limits, review the categories of water quality. If none of the categories of water quality conforms to the specification limits of the parameters of your make-up water, contact a water treatment expert for assistance.

¹ Individual chemical parameter. Contact the Chiller Applications group for additional parameters. If any parameter exceeds the limits in this table, refer to the next category of water quality specification for material recommendations or contact Chiller Applications group. See "Section 8 - Glossary" on page 29 for definitions.

² The make-up water concentration specification limits will decrease as the number of cycles increases.

³ All cooling water systems require chemical additives. Once-through systems may not require chemical treatment. However, the water quality must conform to the make-up water specifications.

⁴ Concentrated cooling tower water circulates in the condenser (heat exchanger).

⁵ A maximum specification of [Clfree]= 2.0 ppm may be required in systems with high nutrient loading and drift.

Section 3 - Non-potable water (surface or low TDS well)

This category includes well water and industrial treated fresh water that have a low concentration of total dissolved solids (TDS), and lake, pond, or river that may require filtration if the concentration of suspended solids exceeds the maximum specification limit for make-up water.

The following table defines the water quality specifications for non-potable water. Parameters marked with an asterisk are the most important make-up water parameters for compatibility with materials of construction. If the make-up water quality has one or more parameters that does not meet these specification limits, review the other categories of water quality. If none of the categories of water quality conforms to the specification limits of the parameters of your make-up water, contact a water treatment expert for assistance.

¹ Individual chemical parameter. Contact the Chiller Applications group for additional parameters. If any parameter exceeds the limits in this table, refer to the next category of water quality specification for material recommendations or contact Chiller Applications group. See "Section 8 - Glossary" on page 29 for definitions.

² The make-up water concentration specification limits decreases as the number of cycles increases.

³ All cooling water systems require chemical additives. Once-through systems may not require chemical treatment. However, the water quality must conform to the make-up water specifications.

⁴ Concentrated cooling tower water circulates in the condenser (heat exchanger).

⁵ A maximum specification of [Clfree]= 2.0 ppm may be required in systems with high nutrient loading and drift.

Section 4 - Low chloride treated sewage effluent (TSE) water

There is no consensus for a single specification for TSE. The state of California has developed a specification ¹ for coliform and total suspended solids (TSS) and approved one category of TSE water for evaporative cooling and two categories of TSE water for closed cooling systems.

• If the TSE water supplier has and consistently conforms to a water quality specification, then only one sample is initially required to evaluate material compatibility.
• If the TSE water supplier does not have a water quality specification, then Johnson Controls requires a minimum of three water samples collected on three separate days, preferably in three different seasons to evaluate material compatibility.
• In all cases, the customer must consistently test water samples and apply treatment to ensure reliable service.

The following table defines the water quality specifications for low chloride TSE. Parameters marked with an asterisk are the most important make-up water parameters for compatibility with materials of construction. If the make-up water quality has one or more parameters that does not meet these specification limits, review the other categories of water quality. If none of the categories of water quality conforms to the specification limits of the parameters of your make-up water, contact a water treatment expert for assistance.

¹ California TSE specification: napasan.com/DocumentCenter/View/276/Appendix-D-Title-22-Requirements-PDF

² Individual chemical parameter. Contact the Chiller Applications group for additional parameters. If any parameter exceeds the limits in this table, refer to the next category of water quality specification for material recommendations or contact Chiller Applications group. See "Section 8 - Glossary" on page 29 for definitions.

³ The make-up water concentration specification limits will decrease as the number of cycles increases.

⁴ All cooling water systems require chemical additives. Once-through systems may not require chemical treatment. However, the water quality must conform to the make-up water specifications.

⁵ Concentrated cooling tower water circulates in the condenser (heat exchanger).

⁶ A concentration of [Clfree]= 2.0 ppm may be required in systems with high nutrient loading and drift.

⁷ The specification for the concentration of ammonia in the make-up water does not apply to stainless steel or titanium materials of construction.

⁸ The concentration of ammonia is lower in the tower water than the make-up water due to partial evaporation to the atmosphere.

Section 5 - High chloride TSE water, geothermal or high TDS well water

This category includes effluent from a wastewater treatment plant or from well waters with a high concentration of total dissolved solids (TDS), including geothermal wells. Water from these sources may require filtration if the concentration of suspended solids exceeds the maximum specification limit for make-up water. The most common limiting parameters for these water sources are the concentrations of sulfate and chloride.

In addition, there is no consensus for a single specification for TSE. The state of California has developed a specification ¹ for coliform and total suspended solids (TSS) and approved one category of TSE water for evaporative cooling and two categories of TSE water for closed cooling systems. Chemical and/or mechanical treatment is required if the water quality cannot support the specification.

• If the TSE water supplier has a water quality specification, then only one sample is required to evaluate material compatibility.
• If the TSE water supplier does not have a water quality specification, then Johnson Controls requires a minimum of three water samples collected on three separate days, preferably in three different seasons to evaluate material compatibility.
• In all cases, the customer must consistently test water samples and apply treatment to ensure reliable service.

The following table defines the water quality specifications for high chloride TSE. Parameters marked with an asterisk are the most important make-up water parameters for compatibility with materials of construction. If the make-up water quality has one or more parameters that does not meet these specification limits, review the other categories of water quality. If none of the categories of water quality conforms to the specification limits of the parameters of your make-up water, contact a water treatment expert for assistance.

¹ California TSE specification: napasan.com/DocumentCenter/View/276/Appendix-D-Title-22-Requirements-PDF

² Individual chemical parameter. Contact the Chiller Applications group for additional parameters. If any parameter exceeds the limits in this table, refer to the next category of water quality specification for material recommendations or contact Chiller Applications group. See "Section 8 - Glossary" on page 29 for definitions.

³ The make-up water concentration specification limits will decrease as the number of cycles increases.

⁴ All cooling water systems require chemical additives. Once-through systems may not require chemical treatment. However, the water quality must conform to the make-up water specifications.

⁵ Concentrated cooling tower water circulates in the condenser (heat exchanger).

⁶ A concentration of [Clfree]= 2.0 ppm may be required in systems with high nutrient loading and drift.

⁷ The concentration of ammonia is lower in the tower water than the make-up water due to partial evaporation to the atmosphere.

Section 6 - Seawater

Seawater is water from the open ocean that has a low concentration of TSS and a high concentration of TDS.

The following table defines the specifications for seawater. Parameters marked with an asterisk are the most important make-up water parameters for compatibility with materials of construction. Options for seawater make-up that exceeds the maximum specification for TSS are:

• Requires the customer to install a full-flow filtration system for the make-up water
• Requires the use of smooth bore tubes

If the seawater make-up has any concentration of ammonia, sulfides, or anaerobic bacteria, the materials of construction for the tubes must be titanium or Duplex. If the make-up water quality has other parameters that do not meet these specification limits, review the other categories of water quality. If none of the categories of water quality conforms to the specification limits of the key parameters of your make-up water, contact a water treatment expert for assistance.

¹ Individual chemical parameter. Contact the Chiller Applications group for additional parameters. If any parameter exceeds the specification limits in this table, refer to the next category of water quality specification for material recommendations or contact Chiller Applications group. See"Section 8 - Glossary" on page 29 for definitions.

² Make-up water concentration specification limits will decrease as the number of cycles increases.

³ All cooling water systems require chemical additives. Once-through systems may not require chemical treatment. However, the water quality must conform to the make-up water specifications.

⁴ Concentrated cooling tower water circulates in the condenser (heat exchanger).

⁵ A concentration of [Clfree]= 2.0 ppm may be required in systems with high nutrient loading and drift.

⁶ Maximum specification limit for ammonia and sulfides applies to CuNi tubes only, there is no limit for titanium or Duplex S22053.

Section 7 - Brackish water

Brackish water occurs at the margins of tidal areas such as harbors, the mouth of a river that flows into the sea, and inland seas.

Typically, brackish water requires filtration. Options for brackish water make-up that exceeds the maximum specification for TSS are:

• Require that the customer install a full-flow filtration system for the make-up water
• Requires the use of smooth bore tubes

If the brackish water make-up has any concentration of ammonia, sulfides, or anaerobic bacteria, the materials of construction must be titanium or Duplex S22053.

The following table defines the water quality specifications for brackish water. Parameters marked with an asterisk are the most important make-up water parameters for compatibility with materials of construction. If the make-up water quality has other parameters that do not meet these specification limits, review the other categories of water quality. If none of the categories of water quality conforms to the specification limits of the key parameters of your make-up water, contact a water treatment expert for assistance.

¹ Individual chemical parameter. Contact the Chiller Applications group for additional parameters. If any parameter exceeds the specification limits in this table, refer to the next category of water quality specification for material recommendations or contact Chiller Applications group. See "Section 8 - Glossary" on page 29 for definitions.

² Make-up water concentration levels may change based on number of cycles.

³ Cooling water requires chemical additives or a non-chemical water treatment device or a combination of both. Once-through systems may not require chemical treatment, but must meet the parameters listed previously.

⁴ Water circulating in the condenser heat exchanger.

⁵ Chlorine, free [Clfree] = 2.0 ppm may be required in systems with high nutrient loading and drift.

⁶ Maximum specification limit for ammonia and sulfides applies to CuNi tubes only, there is no limit for titanium or Duplex S22053.

Section 8 - Glossary

Images of YORK chillers, showcasing different configurations.

• Biochemical oxygen demand (BOD): The measure of biological organisms, such as algae or bacteria (Coliform), in a body of water.
• Ceramic coating: A liquid ceramic polymer composites that can be used to resurface and protect all wet areas on fluid flow components from aggressive erosion/corrosion attack. Typically applied to the tubesheets and the inside of the waterboxes. Coatings are subject to wear and tear and should be inspected annually and maintained as required.
• Chemical oxygen demand (COD): The measure of inorganic contaminates, such as nitrite, that react to oxygen in the water.
• Cladding: This is the process of covering one material with another. Typically, an exotic metal or metal/alloy, which is chosen to be used for protection, is used to cover a steel component, most often a tubesheet or the inside of a waterbox. Cladding is a higher up-front cost, but virtually maintenance free.
• Copper: The industry standard for heat exchanger tubes. Copper offers the best in thermal conductivity and is a good material for workability, which allows for a greater range of tube internal and external enhancement configurations. This typically results in the highest chiller capacity and highest heat transfer. All tubes are suitable for 300 psi waterside DWP.
• Copper nickel (CuNi): A copper/nickel alloy often used for heat exchange tubes. Most commonly offered as 90/10 and 70/30 (% copper / % nickel), these alloys typically offer an increased level of protection at the sacrifice of capacity, efficiency, and cost.
• Cycles or cycles of concentration (CoC): Cycles of concentration represents the accumulation of dissolved minerals in the recirculating cooling tower water as it is evaporated from the cooling tower. Draw-off, or blow down, is used principally to control the buildup of these minerals. Staining and scale build up may result from the precipitation of the dissolved solids.
• Epoxy coating: A protective coating that can be applied to the inside of waterboxes, tubesheets or both. Epoxy coating provides limited protection against corrosion. Coatings are subject to wear and tear and should be inspected annually and maintained as required.
• Galvanic corrosion: A process that degrades metals electrochemically. This corrosion occurs when two dissimilar metals are placed in contact with each other in the presence of an electrolyte, such as salt water, forming a galvanic cell. The resulting electrochemical potential then develops an electric current that electrolytically dissolves the less noble material.
• Holidays: A discontinuity or break in a coating, exposing the bare base metal underneath.
• Monel: Monel is a nickel alloy, primarily composed of nickel and copper, with some iron and other trace elements.
• Sacrificial anodes: Sacrificial anodes serve as an electrode through which electric current flows into a polarized electrical device capturing charged materials in water therefore reducing corrosion.
• Titanium: A very durable material that is extremely resistant to corrosion and erosion. Titanium will offer the highest reliability, but at the highest price and decreased heat transfer. Tube configurations are limited as titanium does not have very good workability and is difficult to enhance.
• Total Organic Carbon (TOC): This is the amount of carbon bound in an organic compound and is often used as a non-specific indicator of water quality or cleanliness of equipment.