Ventless Drying

  • Up to 45% subsidized acquisition costs

  • Save up to 75% on energy costs

  • 100% planning reliability thanks to premium after-sales service

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In industrial processes, drying plays a crucial role – both for product quality and energy consumption. Ventless drying from HARTER stands for maximum efficiency, reproducible results, and utmost cleanliness. Thanks to innovative heat pump technology, heat and moisture are retained within the system, ensuring no energy is lost to the outside.

The result: a controlled, environmentally friendly process with constant conditions – regardless of room climate, season, or ambient air.

How HARTER develops such customized solutions is shown in: How Solutions for Heat Pump Dryers are Created.
The physical principles are described in: Energy-Saving Drying with Heat Pumps.

Do you require a custom solution and/or would you like to test the drying process beforehand?

Development with practical tests in our in-house development center

We are an innovation-driven team and welcome new challenges. HARTER tests your custom solution in the technical center under realistic conditions, optimizes the parameters, and documents the results transparently. Please contact us – we would be pleased to provide you with a non-binding consultation!

Contact our experts now +49 8383 9223‑210 or submit the contact form
2000

Drying systems

in over 20 countries stand for our quality

100

Employees

from all areas ensure a high level of vertical integration

+ 35

Years of experience

in the development of innovative drying systems

Ventless Drying – Principle and Advantages

In ventless drying, the process air is circulated in a closed loop. The air is continuously dehumidified, tempered, and returned to the drying chamber. This keeps the system completely independent of the environment – an advantage for consistent quality and high energy efficiency.

The HARTER Principle:

  • Dehumidification and heating of process air via heat pump
  • Circulation in a closed loop without exhaust air
  • Condensation of moisture within the system
  • Utilization of recovered heat for the next cycle

Your Benefits:

  • Up to 70% energy savings compared to hot air systems
  • No heat loss, as no exhaust air is generated
  • Clean, hygienic process without dust or particle ingress
  • Uniform drying even in complex geometries
  • Low temperatures (30–75 °C) – ideal for sensitive products
  • Independent of climate and season

With this technology, moisture is efficiently removed without energy or air masses being lost. This reduces operating costs while simultaneously improving production conditions.

Ventless
Ventless Drying Systems

Ventless Drying – Applications and Industries

Ventless drying is suitable for almost all industrial sectors – wherever reproducible quality and energy efficiency are required.
HARTER develops customized systems for every application, from food production to electroplating.

Typical Application Areas:

  • Food Industry: Fruits, vegetables, herbs, snacks, protein products
  • Pharma and Chemical: Powders, granules, sensitive active ingredients
  • Surface Technology: Adhesive water drying, electroplating, cleaning
  • Environmental Technology: Sewage sludge, filter cake, residues
  • Material Processing: Plastics, composite parts, metals

System Variants:

  • Chamber dryers / Tray dryers for batch processes
  • Belt dryers for continuous productions
  • Special systems for cleanroom or special applications

Before each design, HARTER tests your original products in its in-house technical center. Temperature, air flow, bed height, and target residual moisture are precisely determined and documented. This results in a validated process with maximum energy efficiency and product quality.

An overview of related application areas is provided by: Industries.

The Process

We dry with dry air and deliver it to the right places: A perfect interplay of air preparation and air guidance provides you with the best possible drying result.

Interface: Airgenex® Dehumidification Technology / Dryer – Moist air is extracted from the drying chamber and supplied to the dehumidification unit.

The pre-cooler pre-cools the air in a first stage. This significantly reduces the compressor’s energy consumption.

Moisture condenses on the fins of the air cooler and drains out of the drying system via the drip tray and condensate drain.

The cooled, dehumidified air is warmed up without additional energy by means of a pre-heater.
The air heater warms the air to the required process temperature.

The process air fan ensures the necessary air exchange between the Airgenex® dehumidification technology and the drying chamber.

Now, the dry, unsaturated air is guided into the drying chamber, where it absorbs the product’s moisture. Thus, the cycle is closed.

Efficiency that pays off.

Our HARTER drying systems save up to 75% CO₂ and are up to 45% governmentally funded.

Reliable – Competent – Long-term

Service that thinks ahead – for years to come

With the HARTER After-Sales Service, you secure a reliable and efficient drying solution for the long term. Whether it’s maintenance, spare parts supply, or technical adjustments – we support your system throughout its entire life cycle and ensure that it delivers optimal results at all times.

Performance Service

Optimal performance through our “all-round carefree package”

Custom Service

Flexible for changing requirements

Expert Service

Fast assistance in case of failure

Lifetime Service

So that the quality is always right

Ventless Drying – Sustainability, Energy Efficiency, and Economic Viability

Ventless drying symbolizes sustainable production. Since no exhaust air is discharged, the heat remains within the system – this saves energy and significantly reduces CO₂ emissions.

Sustainable advantages:

  • Up to 70% energy savings through a closed loop
  • No exhaust emissions and thus no exhaust air treatment required
  • Compact design → less space required
  • Low operating costs through heat recovery
  • Eligible technology according to energy efficiency guidelines

The systems are low-maintenance, durable, and can be easily integrated into existing production lines. Optionally, digital process monitoring, data logging, and automatic humidity control are available – for consistently stable results.

How HARTER implements such processes in various industries is shown in: How Solutions for Heat Pump Dryers are Created.

What our customers say

Not convinced yet? Our customers are thrilled!

“Sometimes it is better to say nothing and let your customers speak for themselves.”
– Regina Mader, Managing Director

“For several decades, we have been using a sludge dryer from Harter in our electroplating shop and are very satisfied with it. The technology and service are reliable and have helped us save a lot of money on disposal.”

Daniel Hutter
Verzinkerei Kriessern AG

“BK Giulini GmbH has been working successfully with Harter GmbH for around 20 years. We are very satisfied with both the dryer technology and the reliability of the complete system. Based on these positive experiences and the very good service, we invested in another drying system of this type in 2023.”

Dimitri Baumbach
ICL Ladenburg / BK Giulini GmbH (ICL Group)

“In our waste incineration plant, we have saved an enormous amount of money by drying our heavy metal-containing hydroxide sludge. The system technology is sustainable and easy to maintain. In retrospect, the investment was a very good decision.”

Stefan Ringmann
KVA Linth

FAQ – Frequently Asked Questions about Ventless Drying

The process operates in a closed air circuit. There is no exhaust air to the outside – the moisture is condensed and discharged within the system.

No energy losses, lower power consumption, stable process conditions, and uniform results.

Up to 70% compared to classic drying systems. The heat remains entirely within the process.

For all sensitive or high-quality materials – from foodstuffs to electroplated metal parts.

Yes. Since no outside air enters the system, the process is particularly clean and controlled – also ideal for food and pharmaceutical products.

Yes. HARTER provides modular solutions that can be easily integrated into existing production lines.

In its technical center, HARTER tests your original products and documents all relevant parameters.

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