Many hydronic cooling systems utilize chilled water or fluid that is cooled through chillers, heat pumps or other means for the purpose of removing excess heat from conditioned spaces or equipment. Piping networks are used to transfer chilled water throughout a building. Most plastic piping materials are ideal for this purpose.

Introduction

In a chilled water system, the chilled water loop consists of pipes and pumps that transport chilled water throughout a building. The chilled water supply temperature is typically in the range of 40 - 55°F (4-13 °C). A chilled water pump circulates chilled water from its source (e.g., a chiller or heat pump) and through the various loads around the building, such as fan coils, radiant panels, air conditioning systems or other types of equipment. As the chilled water passes through the cooling equipment it removes heat from the conditioned space and the fluid temperature increases. The heat is then rejected from the chilled water, typically at an outside location away from the cooling loads.

Materials

Many of the plastic piping materials represented by PPI's Building & Construction Division, such as CPVC, HDPE, PEX, PE-RT, PP-R and PP-RCT, provide economical, safe, sustainable, and reliable piping systems for the transport of chilled water without the cost, corrosion, or environmental issues associated with traditional metal materials such as copper and steel.

Plastic piping materials are approved for hydronic applications such as chilled water in model mechanical codes across USA and Canada including the Uniform Mechanical Code (UMC), the Uniform Solar, Hydronics and Geothermal Code (USHGC), the International Mechanical Code (IMC), and others. Be sure to check local codes and regulations to ensure that the selected pipe material/s meets the requirements.

Read more about each of these piping materials, including the specific product standards to which they are produced, on the webpages for each of the materials.

Advantages

Plastic pipes and fittings do not erode or corrode, preventing the expensive damage that occurs when metallic pipes leak. Plastic piping materials also are resistant to tuberculation and scale build-up which can impede flows, increase pumping costs, and reduce system efficiency and reliability.

Since plastic materials are inherent insulators, thermal heat transfer through the pipe wall is reduced, an important factor when transferring chilled water throughout buildings. This factor can increase overall system efficiency or may reduce the amount of insulation material that is required to reduce heat transfer through the piping network. Radiant cooling panel made with plastic materials offset this insulating effect by reducing the wall thickness and increasing the surface area where cooling is desired.

Other advantages of plastic piping materials for chilled water systems:

• Plastic pipes can reduce installation time and the need for heavy equipment
• Plastic piping materials have the durability and toughness that are necessary to survive commercial jobsite conditions
• Plastic pipes are quieter and absorb most pressure spikes and water hammer
• With clean and flame-free joining systems, the risk of fire is reduced when installing plastic piping systems
• Plastic piping materials are lightweight and easy to transport, reducing transportation and installation costs and improving worker safety
• These materials provide ease of installation with professional appearance
• Plastic pipes deliver lower installed system cost than metal pipes
• No scrap value helps to minimize jobsite theft

Sustainability

In addition to the inherent advantages listed above, plastic piping systems are sustainable choices for numerous reasons:

• No mining operations are utilized to extract ore, as is the case with metals; the raw materials for plastic piping are by-products of oil and gas production that would otherwise result in higher carbon release to the environment.
• Much lower net energy cost to produce plastic as compared with metal pipes
• Smooth wall, excellent flow characteristics reduce pumping costs
• Flexibility can dampen pressure surges and water hammer, reducing pressure spikes and extending equipment life
• Plastic materials do not support biofilm growth, reducing the need for water treatment chemicals such as corrosion inhibitors
• Their light weight reduces transportation energy usage and costs
• Many plastic piping materials are recyclable after their service life is complete

See also

• PPI Presentation: Plastic Pressure Piping Materials for Plumbing & Mechanical Applications
• Building & Construction Related Technical Literature
• Hydronic Industry Alliance - Commercial