Save up to 70% of energy with the DIGICONTROL Economizer module "ems4.ECONO"

Being a company that works in the innovative branches building management, building automation and energy management, GFR always actively takes the opportunity to contribute to a positive future.

The challenges we face very day comprise increased profitability, responsible and sustainable use of resources, environmental protection, value preservation, comfort and security during operation.

The demands of the building owners and operators have changed from initial investment and comfort some years ago to the focus on optimum utilisation of energy and creating the best conditions for the environment during the construction and operation of buildings. GFR meets these demands every single day.

A path-breaking process for the energy-optimised control of energy recovery systems in air-conditioning plants

The DIGICONTROL Economizer ems4.ECONO regulates air conditioning systems in a world-wide unique optimization process according to comfort, environmental and economic requirements and allows a new energy efficiency, which clearly exceeds existing limits of existing standards.

  • Up to 70% energy saving
  • Problem-free integration (in DIGICONTROL and BACnet systems)
  • Easy construction
  • Best possible use of the comfort field
  • Energy- and cost-optimal calculation within the specified room setpoints
  • Scientific development of the control algorithms
  • Increased comfort
  • Increased environmental efficiency
  • Increased efficiency of air-conditioning systems

The idea

Conventional control systems measure the air temperature and humidity and control the energy recovery systems and air treatment stages on basis of the calculated enthalpy. This simple principle is not an optimum solution because the following aspects are not taken into consideration:

  • An energy-optimised utilisation of the area of optimum comfort,
  • An evaluation of air conditioning according to method, energy media and energy efficiency
  • And, arising from that evaluation, an optimised control strategy of the energy recovery system for heating, cooling, humidifying and dehumidifying processes. This saving potential can only be exploited by using the DIGICONTROL Economizer.

The implementation

The DIGICONTROL Economizer contains innovative strategies for controlling the energy recovery system which are based on scientific optimisation algorithms. All Economizer functions and control algorithms are provided in the module ems4.ECONO.

The integration into a new or existing automation system is therefore surprisingly simple: ems4.ECONO is mounted on the top head rail and connected to the controller via bus connectors.

Activating and parameterising the functions is very simple if using the configuration software webCADpro-you are finished in no time. The functions of the Economizer require sensors for measuring the temperature, the humidity of the outdoor air and (if applicable) the temperature after the mixed air damper.

The functional principle and the respective control algorithms were developed in a joint research project (managed by Professor Sokollik) of the University of Applied Sciences Merseburg and GFR. The European Patent Office granted the patent No. 2667278 for the „Procedure and device for controlling the air parameters in rooms“ on the 17 September, 2014. Enormous savings in energy can be achieved. Energy savings of up to 100 % during the process of air treatment can be realized for outdoor temperatures of about 15 to 20 ° Celsius. If you calculate for the whole year, you can reduce the costs on energy by 15-70 per cent.

Reference report: Optimisation of energy consumption and reduction of emissions in a full air-conditioning system at the Fraunhofer Institute Dresden

The most recent example for our innovative history of development are a new process for optimising fans with changing air volumes by means of the “DIGICONTROL proportional pressure control” and the path-breaking and patented process “DIGICONTROL Economizer“. These two optimisation procedures have been retrofitted in an existing air-conditioning plant at the IKTS (Institute for Ceramic Technologies and Systems) of the Fraunhofer Institute Dresden. Impressive savings could be proven after an operating time of 140 days.

Take advantage of our expertise!

For all questions, starting with the planning, implementation, optimization and support of your buildings, you have only one contact person with GFR.



Winner of the GERMAN TGA AWARD 2016

The prize ceremony of the German TGA Award took place in the framework of the “Berlin Energy Days” at the building of the Chamber of Trade and Commerce Berlin on 12 April 2016.

GFR won the prize in the category “Innovative concept in measuring and control technology/building automation” with the project “Optimisation of energy consumption and emission reduction at the Fraunhofer Institute Dresden“. The GERMAN TGA-AWARD is awarded to specialist planners, engineers, architects and manufacturers who operate in Germany. The prize-winning product must have been available on the market and successfully applied in a project. HUSS Medien GmbH is the organiser of the event.

The functional principle of DIGICONTROL Economizer

Conventional control systems are not able to determine the most cost-efficient operating point (set point values in hx diagram for the room) of the air conditioning plant. The most cost-efficient operating point is defined as the condition in which the set point value of the indoor air is placed in such a way in the hx diagram that the air treatment stages only consume as little energy as possible. The set point value limits in the hx diagram constitute the area of optimum comfort.

Area of optimum comfort in the hx diagram

Thermal comfort is not only achieved at a certain set point of room temperature and room humidity but also in a certain area which is defined as the area of optimum comfort in the hx diagram. A temperature range of 20-24 degrees Celsius (max. 26°C) and a relative humidity range of 35-65 %, depending on the outdoor temperature, are common for offices, conference and lecture rooms, class and hotel rooms and living areas. The DIGICONTROL Economizer does not only support areas of optimum comfort being freely defined by the users but also meets the requirements in accordance with DIN EN 15251 categories I through III and DIN 1946 (replaced by DIN EN 13779:2005). Figure 4 shows the unnecessary and energy-intensive cooling of a conventional system which has not been optimised.

Utilising the optimum area of comfort

The indoor air set point values of user-specific or DIN-compliant comfort are not fixed but, as previously described, can be found within the area of optimum comfort. The better the area of optimum comfort is deployed, the better the energy efficiency in the air conditioning system will be. The DIGICONTROL Economizer calculates the cost-optimal operating point within the area of optimum comfort to ensure the most energy-efficient operation and an optimal deployment of the energy recovery system. Figure 5 shows an optimised system in which the indoor air set point values were calculated in an energy-optimised way.

Optimised strategy for controlling energy recovery systems and air treatment stages

The technical structure of the air conditioning plant plays a major role when calculating the optimal operating point within the area of optimum comfort. An innovation of the DIGICONTROL Economizer is the evaluation of air conditioning according to the method, energy media and energy efficiency and the resulting derivation of the sequence.

The Economizer calculates and controls the pre-conditioned air state by means of the energy recovery system in such a way that air conditioning is performed as energy and cost efficiently as possible. The outdoor temperature, humidity, heat load and humidity load are the input variables of the algorithm. The cost factors of the objective function are the specific operating costs of the air heater, the air cooler and air humidifier in €/kWh. The output variables are the set point values for indoor temperature, humidity and air temperature after the energy recovery system and mixed air dampers and the control of the energy recovery system and mixed air dampers.

How can we support you?

Planners and architects:

  • New plants
  • Tender texts
  • Profitability calculation



  • Retrofit, cost estimate, offer


We will gladly advise you, without obligation and send you an offer for the installation or retrofitting of the DIGICONTROL Economizer into your air-conditioning plant.

Take advantage of our expertise!

For all questions, starting with the planning, implementation, optimization and support of your buildings, you have only one contact person with GFR.



Companies and users benefit from DIGICONTROL automation solutions

GFR has over 35 years of experience in the areas of building management, building automation and technical facility management.

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