Less pressure drop in heat pumps and heating systems thanks to highly accurate and non-invasive ultrasonic sensors

category: Heat Pumps and Heating systems

date: 2021-05-21

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A new generation of ultrasonic flow meters generates a significantly lower pressure drop in HVAC end devices. Manufacturers from the sanitary, heating and air conditioning technology thus have access to a new generation of sensors with high measurement accuracy that work more efficiently and economically than all currently available solutions such as impeller or vortex measurement principles.
Ultrasonic flow sensors are gradually replacing standard impeller flow meters and similar mechanical measuring devices in many industrial sectors. The reasons for this are the higher measurement accuracy and longer service life. In addition, the sensors have become competitive in terms of price. Another clear advantage is becoming more and more noticeable with the new generation of ultrasonic measuring devices: the pressure loss in a line is lower than with any other flow meter on the market.

Reduce pressure losses, increase efficiency
Among other things, it is the components that stand in the way of a liquid flow in a line and are responsible for the pressure loss. In order to compensate for this, a pump has to do additional work, which, depending on the level of the pressure drop, consumes a certain amount of energy and thus generates costs, which also has a negative effect on the CO2 balance. Since ultrasonic flow sensors measure without mechanical counters or moving parts, they can reduce these losses and significantly increase the efficiency of heat pumps for example. In addition, this does not make them susceptible to wear or dirt and the high precision of the measurement is retained until the end of its service life.

Allengra increases energy efficiency with new ultrasonic flow meter For comparison: With a generic impeller flow meter, the pressure loss is 390 mbar at 2000 liters per hour. A standard ultrasonic flow sensor can reduce this value to a third (130 mbar). Allengra GmbH, which develops and produces ultrasonic flow sensors and various control valves with integrated pressure and temperature sensors in series, was able to further increase the energy efficiency of the components with the new generation of its ultrasonic flow meters and reduce the pressure drop through a flow sensor with full bore to just 7 mbar at 2000 liters per hour. For companies in the heating, sanitary and air conditioning technology sector, this difference has an impact on the energy consumption of their devices and thus also on the CO2 emissions of their products.

Energy costs at high pressure drop of up to 1780 euros in 15 years In a recent study, Allengra examined the influence on the pressure drop in different flow meters on the market. In addition to the impeller (390 mBar), the Vortex models (75 mBar) were also above the value currently realized by Allengra. Even commercially available ultrasonic flow sensors, including Allengra models, still reach 130 mbar. Even if their previous ultrasonic flow meter is on the lower end of this scale, for Allengra this wasn't enough.

Up to 74% less energy consumption compared to standard components Allengra's new flow meter solution for more energy efficiency is manufactured in a full-bore design and no longer offers any resistance to the water flow through components, has no dead spaces and can be treated like a normal pipe section. In addition, there is low noise emission and high measurement reliability, even in systems with trapped air bubbles.

The higher the pressure drop, the harder a pump has to work to compensate for the difference and provide the same water pressure at all points. The flow rate in a detached house with a floor space of 200 square meters is around 2000 liters per hour. When using the new ultrasonic flow sensor from Allengra, a pump in this case has to generate just 1550 kWh of power over a period of 15 years, a full 74% less than commercially available components. For comparison: If an impeller is used, the pump consumes 5930 kWh, with a vortex flow meter the pump still consumes 2430 kWh; even a standard ultrasonic flow meter is around 2700 kWh.

Using an Allengra ultrasonic flow sensor, such a system would result in total energy costs of only around 465 euros over this period. At a price of €0.30 per kW, the end customer also has up to €1314 more in their wallet after 15 years, which they can save on electricity costs.

High measurement accuracy and low minimum flow rate
The hygienic full-bore design of the sensor is also ideal for use in the food, beverage and pharmaceutical industries. The safe and maintenance-free design does not require any sealing rings. The piezo transducers, which are attached to the outside of the tube, ensure maximum measuring accuracy. The sensor works with a lower minimum flow rate than clamp-on sensors and, in contrast to them, is permanently installed. With a measurement accuracy of 2-3% and a turndown ratio of 1:500, it leaves all other conventional flow sensors on the market far behind.

“A sensor shouldn’t incur costs from pressure drop” “Even in modern heating and heat pump systems, there are still enough obstructions in the flow that increase the pressure drop. The sensor shouldn't be part of it and cause unnecessary costs," says Raul Junker, founder and owner of Allengra GmbH. "We know the problems and requirements of HVAC end device manufacturers and have geared the efficiency and measurement accuracy of our ultrasonic flow sensors to them."

Publications in specialist media:

1.Flow measurement: Less pressure drop thanks to non-invasive ultrasonic sensors [21.05.2021]
2.Less pressure drop in heat pumps and heating systems [21.06.2021]
3.Ultrasonic sensors reduce pressure drop in HVAC end devices [03.11.2021]