Heating is one of the main consumers of energy in moderate temperature zones. The modernization of older and the installation of new, efficient heating systems call for comprehensive data collection, in which pressure sensors play a central role.
The following applications are common:
- Hot water tank monitoring
- Burner control
- Fuel cell heating systems
- Heat exchange/recovery systems
- Heating/flue gas monitoring
Hot water tank monitoring
For many years now even conventional heating systems have been monitored by pressure sensors. The fill level of the hot water tank and, on large systems, the internal pressure of the pressure tank are controlled with the help of a pressure sensor.
Level sensing involves the measurement of relative pressure depending on the fill level and internal pressures require the measurement of absolute pressure in relation to the energy consumption.
Relative pressure sensors of 5 mbar and higher are suitable for level sensing. Absolute pressure sensors of < 1 bar can be used to measure internal pressure.
In order to satisfy various energy-saving demands new burner designs are being developed and applied. These regulate the gas consumption depending on requirements. The heating output is controlled according to the gas pressure in the burner supply. However, the pressure sensors used here must satisfy the compatibility requirements dictated by the composition of the gas (media resistance).
As in this application relative pressure is measured within a range of 20 to 200 mbar, relative low pressure sensors are suitable here.
Fuel cell heating systems
Fuel cells can directly convert chemical energy into electrical energy and are used to generate other forms of energy from municipal gas, for instance. Fuel cell heating systems in single-family homes supply their users with heat and electricity like a miniature heating plant. They are thus classed as CHP or combined heat and power devices and, if planned properly, make for a cost-effective, environmentally-friendly form of heating.
Pressure sensors are used to measure the gas flow and pressure in the fuel cell.
Differential pessure sensors of 5 mbar are used to measure the flow and sensors of 50 to 200 mbar are applied for pressure measurement.
Heat exchange/recovery systems
These systems exploit the energy in the exhaust air to preheat the intake air, for example. For reasons of hygiene fine filters are used which have to be monitored.
Both differential low pessure sensors for filter monitoring (from 2.5 mbar) and relative sensors for pressure adjustment (< 1 bar) are used here.
Compressors are used in HVAC systems to reduce heat by compressing a gas or coolant and returning it to condensation temperature. Compression is usually performed at a high pressure, calling for robust sensors which are resistant to vibration. Heat pumps operate in a similar fashion and require high pressures in an inverse process.
Absolute pressure sensors of > 30 bar are used here.
Heating and flue gas monitoring
Regular monitoring is necessary to control heating functions and exhaust gas emissions. Checks are performed at regular intervals by chimney sweeps.
Barometric sensors are used here which have to be protected against particles and aggressive gases in particular and must be able to detect low concentrations of the former (vacuum) for flue gas analysis.