Improve Dryer Vent Safety With MEMS Pressure Sensors

According to the US Energy Information Administration, clothes dryers rank fifth among appliances that consume the most energy within single family homes, falling just slightly behind refrigerators. Clothes dryers with energy star ratings are highly efficient; however, failure to carry out routine maintenance can significantly impact your energy bill.  Energy star ratings are based on brand new appliances that are properly maintained. Once an appliance receives energy star approval, many manufacturers are not motivated to provide additional features that would enable users to keep their clothes dryer operating at peak efficiency.

The main cause of increased energy consumption within typical clothes dryers is a buildup of lint. Excess lint, in both the lint screen and exhaust pipe, can cause even the most energy efficient machines to consume unnecessary levels of energy. When lint is not removed regularly, exhaust flow is impeded and drying time is extended.  Lint accumulation not only leads to reduced energy efficiency, it can also be a potentially dangerous fire hazard. According to U.S Fire Administration, clothes dryers cause 2900 home fires each year resulting in an estimated 5 deaths, 100 injuries, and $35 million in property damages.

How many consumers do you think consistently clean their lint screens or exhaust hoses? When asked how often they clean the dryer’s lint screen, a college student once replied, “What is a lint screen?”. As you can see, many users would welcome extra features that could alert users when lint buildup is affecting dryer performance.

Detecting Lint Accumulation With Sensors

One method of determining the presence of excess lint is to use a gauge pressure sensor to monitor pressure behind the lint screen. As lint accumulates, pressure decreases behind the screen as air flow is restricted. Manufacturers can use this information to activate a warning indicator to notify consumers to clean the screen.  A simple pressure sensor integrated into dryer vent safety not only helps reduce energy consumption but can also prevent unnecessary damage to properties and lives caused by dryer fires.

Internal testing by NMB Technologies Corporation reveals that the Mitsumi MMR920 Gauge Pressure Sensor is effective in monitoring lint screen buildup. During the test, four heavy cotton towels were continuously washed and dried four times in a row. In the graph below, you can observe that the MMR920 was able to detect an increase in pressure behind the lint screen for each subsequent drying session.

One explanation as to why low pressure sensors have not yet been integrated into clothes dryers is cost – smart controls need semiconductor components to operate. With the rise of IoT, semiconductor manufacturing has soared leading to significantly reduced prices for electronic components. As energy resources transition towards renewable sources, consumers will be more interested in features that increase efficiency. Mitsumi MMR920 Gauge Pressure Sensors can be used to maintain safe operation at maximum efficiency throughout the life of the appliance.