What Is a Thermoelectric Heater/Chiller?

An Engineer's Guide to Refrigerant-Free Liquid Chillers and Precision Heating & Cooling

Process Overview

A thermoelectric heater/chiller is a refrigerant-free recirculating liquid chiller that provides both heating and cooling using solid-state thermoelectric technology. Unlike conventional liquid chillers that rely on refrigerants and mechanical refrigeration, thermoelectric heater/chillers transfer heat electronically using the Peltier Effect.

By simply reversing the direction of the electrical current, the same thermoelectric modules can either heat or cool a circulating fluid. This bidirectional capability allows a single system to maintain highly accurate liquid temperatures over a wide range of operating conditions.

Today, thermoelectric heater/chillers, refrigerant-free liquid chillers, and solid-state liquid chillers are used in semiconductor manufacturing, laboratory equipment, analytical instrumentation, biotechnology, pharmaceutical production, medical devices, photonics, battery testing, solar manufacturing, and industrial OEM equipment where precise liquid temperature control and environmentally friendly operation are important.

Applied Integrated Systems (AIS) designs and manufactures two complementary families of thermoelectric heater/chillers:

• Pelti-Therm™ Recirculating Thermoelectric Heater/Chillers for water/glycol mixtures, silicone fluids, oils, alcohols, and other conventional heat transfer fluids.

• Kool-Pure™ High-Purity Thermoelectric Heater/Chillers for ultra-pure water (UPW), deionized (DI) water, corrosive chemicals, acids, solvents, and other high-purity semiconductor process fluids requiring fluoropolymer flow paths.

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Whether your application requires conventional heat transfer fluids or high-purity chemical compatibility, AIS configures each system around the customer's specific application requirements.

At a Glance

What Is a Thermoelectric Heater/Chiller?

A thermoelectric heater/chiller is a recirculating liquid temperature control system that transfers heat electronically rather than through compressors or refrigerants.

Instead of circulating refrigerant through a compressor, condenser, and expansion valve, thermoelectric systems use semiconductor modules that pump heat whenever DC electrical power is applied.

The technology is based on the Peltier Effect, which allows heat to be transferred from one side of a semiconductor module to the other.

Because the direction of heat transfer changes when the electrical current is reversed, the same module can provide either heating or cooling.

This makes thermoelectric heater/chillers particularly attractive for applications requiring precise bidirectional temperature control.

How Thermoelectric Heating & Cooling Works

Inside every thermoelectric module are multiple pairs of semiconductor elements electrically connected in series and thermally connected in parallel.

When electrical current flows through the module:

• Heat is absorbed from one surface.

• Heat is transported through the semiconductor junctions.

• Heat is released from the opposite surface.

  
  

To maintain stable operation, the rejected heat must be removed using an appropriately designed heat rejection system.

A complete thermoelectric heater/chiller therefore includes much more than thermoelectric modules. Typical components include:

• Thermoelectric modules

• Heat exchangers

• Pump

• Reservoir

• Temperature sensors

• PID controller

• Power electronics

• Safety interlocks

• User interface

• Communications

  
  

The performance of the system depends on how well these components are engineered to work together.

Why Engineers Choose Refrigerant-Free Thermoelectric Heater/Chillers

Engineers increasingly select thermoelectric heater/chillers because they combine precise liquid temperature control with environmentally friendly operation.

Heating and Cooling in One System

Unlike conventional equipment that typically performs one function, thermoelectric systems provide both heating and cooling using the same solid-state modules.

Refrigerant-Free Operation

Thermoelectric heater/chillers eliminate the need for refrigerants by transferring heat electronically rather than mechanically.

Potential benefits include:

• Refrigerant-free operation

• No ozone-depleting refrigerants

• No high-GWP refrigerants

• No refrigerant leaks

• Environmentally friendly operation

• Sustainable liquid temperature control

  
  

For many laboratory, medical, semiconductor, and industrial applications, refrigerant-free technology supports corporate sustainability initiatives while simplifying system design.

High Temperature Stability

Thermoelectric heater/chillers are widely used where stable liquid temperature directly influences process quality, measurement accuracy, or product performance.

Compact Equipment

Because they do not require conventional refrigeration components, thermoelectric systems can often be integrated into compact OEM equipment.

Quiet Operation

The thermoelectric modules themselves contain no moving mechanical parts, contributing to quiet operation.

High Reliability

Properly engineered thermoelectric systems can provide years of dependable operation with minimal maintenance. The Pelti-Therm™ and Kool-Pure™ product familes are specifically designed with high-quality components and modular construction to support long-term reliability.

Choosing the Right Thermoelectric Heater/Chiller

Pelti-Therm™ Refrigerant-Free Recirculating Thermoelectric Heater/Chillers

Pelti-Therm™ systems are designed for recirculating liquid temperature control using conventional heat transfer fluids.

Typical fluids include:

• Water/glycol mixtures

• Silicone fluids

• Alcohols

• Oils

• Industrial coolants

  
  

Common applications include:

• Medical equipment

• Laboratory instruments

• Pharmaceutical systems

• Battery testing

• Solar manufacturing

• Laser cooling

• Industrial OEM equipment

  
  

Pelti-Therm™ systems feature configurable heating and cooling capacities, multiple pump options, compact footprints, and modular designs that can be tailored to the application. Typical specifications include a large range of heating and cooling capacities, operating temperatures from -10°C to 80°C, and PID temperature control with application-dependent accuracy of ±0.1°C or better.

Kool-Pure™ High-Purity Thermoelectric Heater/Chillers

Kool-Pure™ systems extend the benefits of thermoelectric heating and cooling to semiconductor and other high-purity applications requiring contamination-free fluid handling.

These systems are designed for fluids such as:

• Ultra-Pure Water (UPW)

• Deionized Water (DI)

• Sulfuric Acid

• Hydrochloric Acid

• Hydrofluoric Acid

• SC-1

• SC-2

• SPM

• Solvents (non-flammable)

• Other corrosive process chemicals

  
  

Unlike conventional liquid chillers, Kool-Pure™ systems incorporate chemically inert fluoropolymer flow paths that help preserve fluid purity while providing precise refrigerant-free heating and cooling.

Typical applications include:

• Semiconductor wet benches

• Chemical delivery systems

• Chemical recirculation loops

• Wafer cleaning equipment

• Process development tools

• High-purity chemical processing

  
  

Environmentally Friendly Cooling and Heating

As industries continue to focus on sustainability, thermoelectric heater/chillers offer an environmentally responsible approach to precision liquid temperature control.

Because these systems transfer heat electronically, they eliminate the need for conventional refrigerants.

For many applications, thermoelectric technology provides:

• Refrigerant-free liquid cooling

• Refrigerant-free heating

• Environmentally friendly temperature control

• Zero direct refrigerant emissions

• Reduced environmental impact

• Sustainable precision liquid temperature control

  
  

For engineers seeking eco-friendly industrial chillers, refrigerant-free liquid chillers, or green process cooling solutions, thermoelectric technology offers an attractive alternative for many precision applications.

The AIS Engineering Approach

Applied Integrated Systems believes that the best thermoelectric heater/chiller is one engineered around the customer's application rather than selected from a fixed catalog.

Every project begins with understanding:

• Heat load

• Required temperature range

• Fluid compatibility

• Flow rate

• Temperature stability

• Reservoir volume

• Pump requirements

• Communications

• Installation footprint

• Electrical requirements

  
  

Rather than integrating off-the-shelf components into a standard package, AIS engineers configure complete thermoelectric heater/chillers around each application's specific operating requirements.

Whether the application is best served by a Pelti-Therm™ refrigerant-free recirculating heater/chiller or a Kool-Pure™ high-purity thermoelectric heater/chiller, AIS routinely develops application-specific configurations. These configurations are provided at no additional engineering charge, allowing customers to obtain a system optimized for their application without incurring engineering fees typically associated with custom equipment.

Engineering Design Checklist

Before selecting a thermoelectric heater/chiller, consider:

Process Requirements

☐ Required heating capacity

☐ Required cooling capacity

☐ Operating temperature range

☐ Temperature stability

☐ Heat load

Fluid Selection

☐ Conventional heat transfer fluid or high-purity process chemistry

☐ Material compatibility

☐ Flow rate

☐ Pressure requirements

Controls

☐ PID control

☐ Temperature sensor accuracy

☐ Communications

☐ Alarm functions

Mechanical Integration

☐ Installation footprint

☐ Heat rejection method

☐ Electrical service

☐ Future expansion

Frequently Asked Questions

What is a thermoelectric heater/chiller?

A thermoelectric heater/chiller is a refrigerant-free liquid temperature control system that provides both heating and cooling using the Peltier Effect.

What is the difference between Pelti-Therm™ and Kool-Pure™?

Pelti-Therm™ systems are designed for conventional heat transfer fluids such as water/glycol mixtures and other industrial coolants. Kool-Pure™ systems are engineered for high-purity applications using fluoropolymer flow paths compatible with DI water, UPW, and many corrosive process chemicals.

Why are thermoelectric heater/chillers considered environmentally friendly?

They operate without conventional refrigerants, eliminating the need for ozone-depleting refrigerants or high-GWP refrigerants while providing precise liquid temperature control. The Pelti-Therm™ product literature also highlights the elimination of ozone-depleting chemicals and toxic Freon substitutes as a key environmental benefit.

Can AIS configure a system for my application?

Yes. AIS routinely configures thermoelectric heater/chillers around the customer's specific operating requirements and provides these application-specific configurations at no additional engineering charge.

Continue the Conversation with an AIS Engineer

Selecting the right thermoelectric heater/chiller involves much more than choosing a heating or cooling capacity. The most effective solution depends on understanding the complete application—including the heat transfer fluid or process chemistry, required temperature stability, flow rate, heat load, installation constraints, and control requirements.

Whether your application requires a Pelti-Therm™ refrigerant-free recirculating heater/chiller for conventional heat transfer fluids or a Kool-Pure™ high-purity thermoelectric heater/chiller for semiconductor and chemical process applications, the engineering team at Applied Integrated Systems is ready to help.

Explore our complete range of thermoelectric heater/chillers, refrigerant-free liquid chillers, and high-purity thermoelectric heater/chillers, or request a customized quote. AIS will configure a system specifically for your application at no additional engineering charge.