Building Technology Laboratory Measurements for heating, ventilation and air-conditioning technology

Since its initial accreditation in 1997, the the Building Technology Laboratory has been active in the field of measuring and testing air-to-air heat exchangers. For this purpose it operates an internationally recognized test facility. This is designed for the measurement of heat exchangers up to 7'000 m³/h according to the European standard EN 308 and the standard of the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE).

In the laboratory, measurements are carried out on heat recovery systems for the European certification Eurovent and the US Association for Air Conditioning, Heating and Refrigeration AHRI.

• Recuperative and regenerative heat exchangers such as rotary heat exchangers and plate heat exchangers
• run-around coil systems and heat pipes

One of the core skills of the Building Technology Laboratory is carrying out testing on residential ventilation units. For almost ten years now, the laboratory has tested the performance of ventilation units.

The corresponding test rig was constructed as part of the «Rational Use of Energy in Buildings” research program from the Swiss Federal Office of Energy. The main goal of the project was to offer full technical testing of residential ventilation units with heat recovery and heat pumps at reasonable costs, and thus to make a contribution towards ensuring and further improving the performance quality of the units. The test rig has been designed for units of 40 to 1,200 m³/h. Large-scale units of up to 7,000 m³/h are tested on the test rig for air-to-air heat recovery devices. Tests are performed according to the European standards EN 13141-7 and EN 13141-8, among others.

Customers include manufacturers from across Europe. Among others, the tests are used to obtain the energy label for residential ventilation units (RVU) according to EU regulations 1253/2014 and 1254/2014. The measurements are also used for the Swiss declaration of residential ventilation units at the association energie-cluster.ch, for approval from the German Passive House Institute and for approval in Belgium.

However, the specialists also work on systems that are already in operation. This includes the detection of leaks in ventilation ducts or unbalanced ventilator settings that constantly lead to excessive energy consumption and noise emissions. For example, in the current «Energy Efficiency of Ventilation Systems» (EFFILUFT) project financed by the Swiss Federal Office of Energy, the energy efficiency of a large number of medium-sized and large ventilation systems has been inspected.

Tested Devices

• Air handling units with supply and exhaust air
• Recuperative and regenerative heat recovery systems
• Exhaust-air heat pumps for the heating of supply air and/or water

Contact: Prof. Heinrich Huber

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The professionals at the Building Technology Laboratory test the thermal environment of all types of rooms directly on site. This is made quantitatively by testing the thermal comfort according to the international standards ISO 7730, EN 15251 and ASHRAE 55. The indoor air temperature and dew point are measured, as are the wet-bulb temperature, air velocity, radiant power in the room, operative temperature and the dry heat loss. Data is often recorded over a prolonged period lasting several weeks by installing the special measuring instruments on site and then analyzing the data back in the laboratory.

From the recorded data, the draft risk , turbulence level of the air, optimum operating temperature, Predicted Mean Vote (PMV) – a statistically founded statement on the thermal comfort of the user taking into account clothing and the degree of activity – and the Predicted Percentage Dissatisfied (PPD) are all assessed.

The laboratory also offers an additional service – namely the site identification of comfort in the rooms as experienced by the users. The Building Technology Laboratory has developed their own online questionnaire and evaluation method for this purpose. Measurements are made according to the Swiss and European standard SN EN 15251.

The professionals at the Building Technology Laboratory specialize in acoustic testing. They are supported in their work by a state-of-the-art infrastructure. The in-house acoustic test rig is comprised of two rooms – a reverberation chamber and an anechoic chamber. The two rooms are connected by an air duct with a ventilator and attenuators. In contrast to closed acoustic testing rooms, this also allows for acoustic testing to be made on ventilation systems and components using air flows, as the air – muffled accordingly – is able to circulate.

Aerodynamic measurements are carried out on the air flow test rig, in particular tests on air volume flow but also measurements of pressure losses on various ventilation  air conditioning components. At the heart of the process are reference flow rate meters, with which extremely precise volumetric air flow measurements are possible.

A further specialty of the Building Technology Laboratory is precise trace gas measurements. This includes volumetric air flow and leakage measurements in tunnels, air exchange rate and air age measurements in rooms, leakage measurements in buildings and checking the effectiveness of extractor hoods. 

This procedure is based on the controlled addition of a trace gas that can be easily detected and is not found in the natural surroundings of the analyzed air, then registering the concentration at the measuring point using a suitable measuring method. For example, this measurement can then be used to connect the trace gas concentration in a flow of air to the volumetric air flow.

What we offer / Measurement Examples

• Ventilation effectiveness: Air exchange efficiency, air renewal and ventilation efficiency, eliminating pollutants
• Air-mass flow, air exchange, air age and short circuits in ventilation systems
• Leak tests and airtightness tests on ventilation units
• Exhaust-air transmission on rotary heat exchangers
• Analyzing the spread of pollutants or odorous substances and refrigerants

Contact: Frank Gubser

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Tests are made using water on the hydraulic test rig. In this way, pressure loss coefficients, valve characteristics and pump characteristics can be determined.

The Swiss Gas and Water Industry Association (SVGW) requires manufacturers of sanitary components to specify the pressure losses on their components, which then have to be validated by an independent test laboratory. The building technology laboratory is on hand to carry out these measurements.

Contact: Frank Gubser

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Thanks to the various different test rigs in the laboratory, the specialists are able to offer a wide range of additional measurements and testing procedures.

What we offer / Measurement Examples

• Thermal measurements on components such as exhaust light fittings
• Thermal output measurements on components such as trench heaters, cooling beams etc.
• Thermal measurement and pressure losses on air-to-water heat exchangers and air heat exchangers
• Inspection of controllers for cooled ceilings and floor heating
• Measurement of humidifier and dehumidifier performance
• Drying performance of tumble dryers
• Visualization of flows in devices
• Casings of air handling units: mechanical strength, air leakage, heat transfer coefficient/ thermal transmittance, thermal bridging factor and acoustic insulation according to EN 1886

Contact: Prof. Heinrich Huber

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Beyond its accredited activities, the laboratory also specializes in clean room technology and indoor air quality applications.

It runs special test rooms for investigating the effectiveness of ventilation concepts for rooms in the healthcare sector (e.g. operating theaters, intensive care units or isolation units). Measurements are made here for the purpose of certification or the further development of devices, based on the Swiss standard SWKI VA 105-01, international standards and in-house testing specifications, among others.

Testing facilities and measuring equipment are also available for ensuring water quality in buildings, and can be adapted according to individual requirements.
As part of field tests, the hygienic conditions of the system are assessed on site and a relevant set of measures is drawn up.

Customers typically include manufacturers of devices, components and systems, planners of HVAC and sanitary systems, system operators, facility management companies and property owners.

Contact: Dr. Benoit Sicre

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A wide range of measuring equipment can also be used outside the laboratory. The services range from recording temperature and humidity with mini data loggers right up to complex energy monitoring and comfort testing. Long-term measurements with many data points are recorded using both connected and state-of-the-art wireless solutions. The collection of data is made via a network with PLC solutions. Due to changes of value data is gathered using a process control system. It is thus possible to record several thousand data points at a sampling rate of up to 200 ms over a measurement period lasting over one year. Data can be remotely monitored, analyzed and saved at any time using a 3G mobile router.

Experienced research associates and lecturers analyze the systems on site. A significant potential for improvement is often identified on the pass. By means of the existing system documentation and the analysis of the measured data, conclusions can be made on any malfunctions and the potential for process optimization. Moreover, data can also be used for validating simulation models.

Messured values

• Temperature
• Humidity
• Air velocity
• Thermal comfort
• Air volumes
• Pressure difference
• Thermal and cooling energy
• Electrical energy
• Operating times and operating steps
• Metering pulses
• Solar radiation
• GPS data

Reference projects

• Long-term measurements for the “Passenger ship Lake Lucerne” project by the Swiss Commission for Technology and Innovation
• “Replacement strategies for electric water heaters under consideration of the whole building heating infrastructure” project by the Swiss Federal Office of Energy

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