Technische Universität Braunschweig

Building description

NameTechnische Universität Braunschweig
LocationBraunschweig, Germany
Building OwnerTechnical University Braunschweig
Partnersynavision GmbH, IGS TU Braunschweig
Type of buildingUniversity
Use typeOffices and Laboratories

The Building

The campus consists of together by more than 200 buildings which have been built between 1871 and today whereas the majority of the buildings date from 1950-1960. To ensure HVAC performance quality regarding optimal energy use and comfort, a generic QM approach has been established. This QM-Process is tested at 5 buildings on the campus in dialogue with the building management department of TU Braunschweig.

Quality Management

To develop a Campus-wide QM-Process 3 Tools are used. Using the synavision Performance Test Bench, Germany (, target values have been digitally defined using active functional specifications. These have then been compared to building automation data form real operation. To improve (or guarantee stable) comfort, surveys were undertaken frequently with the Comfortmeter-software from Factor 4, Belgium ( To use the Campus-wide BACnet network, a BACnet gateway has been installed to retrieve and store data from BACS in various buildings. Only in particular cases non-available datapoints (e.g. energy meters from AHU, Pumps etc.) have been gathered with mobile sensors.

Building owner and Facilitator: Responsible for the building operation and implementation of measures ESCO: Provision of the QM service: Data acquisition, functional performance tests, comfort survey

The generic process was demonstrated with the system component air handling unit (AHU) which is responsible for most of the energy demand on site but can also be applied to other HVAC systems. An AHU can be divided into 4 major classes which represent 90% of all existing combinations. An analysis of all AHU types within each building on the campus had shown that from 27 AHU’s 19 are from type A (heater and heat recovery) which could be tested with one single template on synavision’s performance test bench

Building’s technical equipment

BuildingSystem/typePower, source/fuel type, size, circuits …Selected for QM-process
  • Air handling unit (AHU01)
  • Air handling unit (AHU02)
  • Heating circuit (HC01) 
  • Heating circuit (HC02)
  • Heating circuit (HC02)

  • District Heating
  • Electricity
  • Air handling unit
External University Building - Münster
  • Air handling unit SP5
  • Heating circuit North SP7
  • Heating circuit South SP7
  • Cooling 1 SP7
  • Cooling 2 SP7
  • Cooling SP5
  • Air handling unit SP7-1
  • Air handling unit SP7-2
  • Air handling unit EDV SP7
External University Building - Heidelberg
  • District heating
  • FBH
  • Static heating
  • Ventilation East
  • Air heater laboratory of physics
  • Air heater of clean room
  • District cooling
  • Ventilation West 
  • Microscopy
  • Ventilation TEM
  • Cooling Unit KM1
  • Cooling circuit (KK01)
  • Cooling circuit (KK02)

* only selected systems which were analysed are listed

Energy Performance (Evaluation of Savings)

Baseline (kWh/a)Savings (kWh/a)%Savings (kg/a)
AHU End-Energy7 477 000 kWh/a 2 683 000 kWh/a16488 000

Saving potential refers to buildings which are located at the TU Braunschweig Campus only (Forumsgebäude, BRICS and PVZ) and is the potential end-energy and carbon savings for AHU’s with a volume flow rate of more than 1,000 m³/h. Annual monetary benefits include savings in energy costs as well as other cost savings such as expenses for maintenance and repair.

Operational Performance

Performance issues which have been identified are:

  • Supply air temperature set-point
  • Too high or low set-points for supply temperatures of the heating and cooling- coil
  • Wrong schedules for operation of fans
  • Simultaneous operation of heating and cooling circuits
  • Pump was running even when there was no heating or cooling demand
  • Frequent on/off changes affecting the life span and controllability
  • Faulty control sequence between heating, cooling-coil, heat recovery and free-cooling
  • Missing night- setback operation mode with lowered system temperatures

Besides direct cost savings for the operation of HVAC systems, there is also indirect saving potential such as the life span of equipment, labour costs for the facility manager in all commissioning phases and not least costs due to comfort loss of users.