HOF Enterprise Group

Specialists as sought-after partners for industry

The HOF group of companies, with the companies HOF Sonderanlagenbau GmbH and HOF Prüfsysteme GmbH, has been in the possession of the central Hessian entrepreneur Hans-Georg Hof for several decades. Both companies are specialists in their branch, with their high level of know-how and many new innovative ideas laid the foundation for the high technological competence of the group.

Welcome to HOF

HOF Sonderanlagenbau GmbH has been the leading specialist for manufacturing
individual freeze drying systems, loading and unloading systems
and freezing and thawing equipment for over 30 years.

Focus on your product

Individually designed, planned and manufactured – with state-of-the-art technology

We let knowledge grow

Our know-how is the basis for your success

Communication & media

Knowing what is important



HOF Sonderanlagenbau GmbH
Ludwig-Rinn-Str. 1-3
35102 Lohra

Phone + 49 6462 9169-0
Fax + 49 6462 9169-199


Mornshausen site:

HOF Sonderanlagenbau GmbH
Vor dem Langen Loh 2
35075 Gladenbach-Mornshausen

Phone + 49 6462 9169-0
Telefax + 49 6462 9169-199



New special ACHEMA website

How time flies! And we are now focusing on important upcoming events, such as the world's leading trade fair for the process industry, ACHEMA, which will take place next year in Frankfurt.

ACHEMA positions itself as a technology platform and as the most important driving force for the international process industry. The preparations are already in full swing and we will of course be represented there again as the international specialist market leader.

In the run-up to the trade fair and until its start on April 4, 2022, we will keep you up to date on our special ACHEMA website with information about HOF and our trade fair activities.

Look forward excitedly to this event!

Best regards

Dr. Alexander Hof - CEO


ACHEMA 2022 - World Forum for process industries

It will be a modern, interactive and always up-to-date exhibition which will offer a unique range of topics, exciting focused themes and new event formats.
ACHEMA will once again gather experts, qualified users and prospective customers from all over the world to share knowledge on these topics.

Manufacturers and service providers from over 50 countries will show their products for chemical, pharmaceutical and biotechnological areas as well as for energy and environment. ACHEMA is thereby the most important driving force for the international process industry.

As a technology platform and international marketplace for the latest trends in technology, ACHEMA drives developments forward in all sectors of the process industry. There is no other event in the calendar that offers such a comprehensive mix of pioneering technology and global networking - an up-close experience that appeals to all the senses and inspires sustainable connections.

Source reference Text: ACHEMA / DECHEMA Exhibition GmbH

More information here >


HOF presents a newly robot-assisted loading and unloading system

The need for high quality loading and unloading systems for freeze driers in the pharmaceutical and biotechnological industry, as well as their technological requirements, is increasing.

In the past, new developments in the area of loading and unloading systems have therefore been continuously implemented.

More information here >

For the sixth time in a row TOP 100

We are very pleased to announce that HOF Sonderanlagenbau GmbH from Lohra has once again made the leap among the best in the 28th edition of the TOP 100 innovation competition. And for the sixth time in a row!

Prof. Dr. Nikolaus Franke
Ranga Yogeshwar

“It is a great pleasure to be among the winners again. We would like to thank all employees for their motivation and innovative strength and of course our customers for the regular exchange of knowledge."

Kind regards,
Dr. Alexander Hof


HOF will also be among the medium-sized innovation elite in 2021

Since 2016, HOF has been awarded the TOP 100 seal for the sixth time and is once again one of the most innovative companies in Germany.
The TOP 100 seal was awarded for the 28th time and honors Germany's innovation elite in several categories. This award honors particularly innovative companies from a wide variety of industries. The award is based on an independent test based on a scientific system by the scientific director of TOP 100, Prof. Dr. Nikolaus Franke.

Which innovative measures particularly distinguished HOF, among others?

Here is a selection of the most important measures taken by HOF, based on the following categories:

Top management promoting innovation, innovation climate, innovative processes and organization, external orientation / open innovation and innovation success, as well as entrepreneurial reactions to the corona crisis.

  • The managing director initiates and pursues innovative development projects himself. In addition, special working hours are granted for innovation projects so that those involved Employees can act and react flexibly. At the same time, the idea of ​​innovation not only spans the products and services of HOF, but also the sustainability of the company.
  •  There is a daily and continuous exchange of knowledge between mechanical and electrical construction as well as software development. That promotes the individual personal idea development. At the same time, practical implementation in all Project phases are goal-oriented and accompanied intensively.
  • The in-house quality management manages and organizes the collection of ideas for the various areas. The evaluation and implementation is carried out by the management level supervised. In addition, an external QM consultant is involved in the management of the processes involved.
  • Meetings are held quarterly with the department heads and an external one Management consultant for quality and improvement management. There will be additional Ideas and innovations introduced are discussed, documented and followed up. Thus becomes a Processing or treatment of 100% of all submitted proposals is guaranteed.
  • Thus possible bottlenecks and delivery difficulties of individual suppliers in the Corona crisis can be compensated, exists for all components that we need for our systems, a flexible pool of suppliers.
  • Maintenance work on pharmaceutical freezers has been carried out for our customers in Japan Products conducted via web meeting. A team of experts was involved for three days and has the maintenance work of the systems is instructed via live transmission. There were also plants of our customers in Australia and USA set up under instruction via video conference, in operation taken and validated.
  • As a prophylaxis for the Covid emergency, a group of service technicians was established in the company optional in order to be quickly ready for service for customers in the event of service.

The scientific director is very impressed by the award-winning medium-sized companies: "The TOP 100 companies have consistently aligned themselves to be as innovative as possible," said Prof. Dr. Nikolaus Franke.

In essence, it was about the question of whether innovations are the result of a planned procedure or a coincidental product, i.e. the repeatability of innovation achievements. And about whether and how the corresponding solutions will establish themselves on the market

HOF has successfully asserted itself in this demanding selection process and will therefore again be one of the most innovative companies in Germany in 2021.

Award ceremony by mentor Ranga Yogeshwar

Instead of the previous award ceremony in summer, a year-end event is planned for November. The TOP 100 final as part of the German SME Summit on November 26, 2021, in the Forum am Schlosspark in Ludwigsburg.
The science journalist Ranga Yogeshwar will personally congratulate the successful companies, he has accompanied the innovation competition as a mentor for ten years.

Bildquelle: www.TOP100.de

CryoBlizzard - Next generation of freeze drying and blast freezing

HOF has developed a new process, which uses ambient air as a refrigerant that exceeds the current requirements for freeze drying and blast freezing in the long-run.

Currently, the entire industry is in upheaval due to the social and political rules and regulations in regard to climate change, generating a level of uncertainty for many operating companies. Frequently asked questions refer to the problem of environmental compatibility, official regulations and directives as well as the availability and price development of operating media. This concerns refrigeration in particular, as the established technologies in this field are increasingly restricted by political regulations, bans and shortages. For installations with a service life of more than 30 years, operating companies focus especially on future-proof design, reliability and quality of their plants. Energy efficiency, safety, selection of components, documentation and durability are also crucial factors.

[Translate to Englisch:]

HOF CryoBlizzard - a technology sets new standards

As an innovative market leader, HOF always puts emphasis on customer needs and market demands. Together with Mirai Intex (https://mirai-intex.com/de/startseite/) as a partner, the HOF CryoBlizzard has been developed as a new technology for our market segment.

A HOF freeze dryer from 1998 was retrofitted especially for this R&D project. The plant is a freeze dryer with a batch capacity of 40 kg for insulin production. Before this retrofit, refrigeration was achieved by two refrigeration sets, each containing 12 kg of the refrigerant R404A (GWP100 = 3922). The process plant was controlled by a Siemens S5 control system.

Great performance with homogeneous temperature distribution

The overall retrofit has upgraded the lyo to a new refrigeration process, the HOF CryoBlizzard and to the current S7-1500 control system. With this new process, the refrigeration system consists of redundant cold air machines which are connected to a central primary tank in a modular system. The primary tank supplies the consuming units, such as shelf stack, ice condenser or blast freezer directly with the refrigerant medium and can therefore provide large capacities with homogeneous temperature distribution, all within a very short time. The usage of such a primary tank results in the fact that the consumption of cooling water and the power remain constant and no load peaks occur during the supply. Additionally, the cooling water consumption was reduced by half.

Air as refrigerant is free of charge and always available

The cold air machines from Mirai Intex are chillers which operate with air as a refrigerant using the Brayton cycle process. The maximum overpressure in the machines is 3 bar(a) and can be compared to that in a bicycle tire. This makes these machines particularly safe and environmentally friendly. Furthermore, no special requirements result in regards to the machine room set-up, employee training and recurrent testing. And in addition to all this, air as a refrigerant is free of charge and always available, has a GWP100 value of 0 (zero) and is therefore not affected by any regulations.

“As an innovative equipment manufacturer, we knew thatwe have to come up with a new way forward - for our customers. The advantages of air as a refrigerant are obvious. Air is available, non-flammable, non-toxic and poses no risk of suffocation. Air has no GWP value and is therefore not subject to the F-Gas Regulation or any other directives. That is the future!”, says Oliver Fleischer from the refrigeration engineering and service management department at HOF.

The HOF CryoBlizzard turbocompressor, oil-free and almost wear-free

The refrigeration circuit is driven by an air-bearing supported, oil-free turbo compressor–expander unit that runs with up to 88000 rpm and virtually no wear. The refrigeration medium is cooled in a heat transfer unit, integrated into the chiller. The air that is heated this way, is aspirated by the turbocharger and compressed (steps 1 to 2). Subsequently, the energy in the gas chiller is dissipated to the environment and cooled down (steps 2 to 3). In an inner heat transfer unit, the recuperator, the air is strongly cooled down (steps 3 to 4) and then relaxed for effective use in the expander (steps 4 to 5). This work is returned to compression. The energy is now absorbed through heating of the air in the cold medium/heat transfer unit (steps 5 to 6). After the air in the recuperator has been heated again (steps 6 to 1), it is aspirated by the compressor and the cycle starts anew.

With HOF CryoBlizzard - renewing existing systems as a retrofit or implementing new systems

The modular design enables the capacity of the HOF CryoBlizzard to be scaled up or down as needed. This allos its adaption from small freeze dryer units all the way to a central cooling system for complete factories. Existing plants can be retrofitted and new plants can be implemented. With the HOF CryoBlizzard, HOF has developed a future-proof solution for freeze drying and blast freezing which is not only safe for employees and the environment, but also sets new standards with regard to the quality and availability of the application. Therefore, the HOF CryoBlizzard is another alternative technology by HOF to solve the GWP-issue of synthetic refrigerants in the long-run.

In cooperation with the project partners:


Refolution Industriekälte GmbH

We are especially happy, that the technological magazine „DIE KÄLTE + Klimatechnik“ has published an article about our technology already in its most current issue. Source: Alfons W. Gentner Verlag GmbH & Co. KG, Fachmagazin „DIE KÄLTE + Klimatechnik“, Article "Natürlich am besten", issue 01.2020, pages 18 - 19.

For more information on the innovative development, please contact Mr. Oliver Fleischer (Phone: 0049 6462-9169-228 - Email: oliver.fleischer(at)hof-sonderanlagen.de) or any other HOF representative.

Important about SIGRAPH and EPLAN 5

Since the existence of HOF Sonderanlagenbau GmbH all switchgear documentation (wiring diagrams) was prepared at HOF electrical engineering. From 1990 to 2004/2005 we used SIGRAPH and from 2004/2005 to 2012/2016 we used EPLAN 5, later EPLAN Electric P8.

Due to manufacturer-related changes we would like to draw your attention to the following announcements:

Sigraph announcement:

The CAE system SIGRAPH, used to create circuit diagrams until 2004, has already been discontinued by the manufacturer for some time. Economic processing of the circuit diagrams is therefore unfortunately no longer possible. We can therefore process changes in SIGRAPH diagrams only to a limited extent and must discontinue support for these circuit diagrams from 2022.

For larger modifications, we recommend converting the circuit diagrams to EPLAN P8.

EPLAN 5 announcements:

The CAE system EPLAN 5, used to create circuit diagrams between 2004 and 2016, has been replaced by the EPLAN P8 system. As of version EPLAN P8/2.8, EPLAN 5 can no longer run in a system environment. Furthermore, operation under Windows 10 is not released.
In the future, EPLAN 5 projects must therefore be migrated to P8 to enable further processing.

Bernd Becker (Head of Electronics Engineering)

"If modifications to your affected systems are planned, we will be happy to support you with a future-oriented solution."

Would you like to know more?

Ask us a question!