MEMS Technology Supports Efficient HVAC Systems

Energy saving has been implemented in the past due to a sense of crisis over the depletion of future natural resources. In recent years, energy saving efforts have been further strengthened from the perspective of global warming countermeasures, such as greenhouse gas reductions, and decarbonization. Concerns about energy security and energy instability in current global affairs also contribute to urgency surrounding energy initiatives. Here, we will focus on electric power usage, which continues to increase even amidst the ongoing calls for energy saving, and present what is required for energy saving and the important role that MEMS technology will play in achieving high goals for energy usage reduction.

Energy Saving Changes with the Times

The demand for global energy continues to increase, both for primary energy (as raw material,) and for final energy. In particular, the share of electricity usage, which is expected to increase as global decarbonization progresses, continues to grow worldwide. China and India in particular, which are experiencing remarkable economic growth, are showing rapid increases in their power usage.

In recent years, the increase in electricity usage by air conditioning and other HVAC equipment due to global warming has also become an issue.

According to the IEA (International Energy Agency), the electricity demand for space cooling by air conditioners is expected to triple by 2050, accounting for 37% of the total increase in electricity demand. The widespread use of air conditioners will not only increase electricity usage, but also greenhouse gas emissions. HVAC equipment is required to have high energy-saving performance and low greenhouse gas emissions, and it will be even more important to promote the widespread use of products with these capabilities.

What It Takes to Save Energy on HVAC Equipment

To achieve energy savings on heating, ventilation, and air conditioning (HVAC) equipment, it is important to properly manage energy and use it efficiently. In addition to reducing energy usage, it is also necessary to develop and adopt new technologies, such as the use of environmentally friendly materials. This section presents the latest sensing technologies that HVAC equipment incorporates to use energy efficiently, as well as the use of MEMS to support new technologies.

Sensing Technologies to Reduce Energy Usage

A typical technology used for energy saving is the inverter. Installation of inverters enables lower energy losses, prevents malfunctions and stoppages, and ensures a stable output supply. Inverters are used in a wide variety of home appliances, but the use of inverters in room air conditioners is high, and it is estimated that about 80% of air conditioners in widespread use today are equipped with inverters.

This is why sensing technology has been attracting attention for further improving the energy efficiency of air conditioners. Today, IR sensors have been developed to detect the presence of people in an area and to provide targeted heating and cooling, thereby contributing to the efficient operation of equipment by eliminating energy waste.

Other HVAC equipment besides air conditioners include heat exchange ventilators that use gas sensors to detect CO2 concentration in a space and automatically control ventilation, and air purifiers that use separate sensors from the main unit to sense isolated locations and operate efficiently. The HVAC sensors in these devices utilize MEMS technology, and it is forecast that MEMS sensors will continue to be an important piece in achieving energy savings.

New Technologies and HVAC Sensors

Air conditioners and other HVAC equipment use energy-efficient heat pump technology. Heat pumps use refrigerants for cooling and heating by drawing heat from the air, and CFC gas is used as the medium.

Currently, there are two types of CFC gases used as refrigerants in the world: HCFCs (hydrochlorofluorocarbons/specified CFCs)¹ and HFCs (hydrofluorocarbons/alternative CFCs)². While the use of refrigerants allows efficient heat transfer, CFC gases have a high environmental impact, so regulations are being implemented and new refrigerants are being developed at the same time. One such new refrigerant is R32. Although R32 is a type of HFC, it has an ozone depletion potential of 0 and a global warming potential of 675, one-third that of conventional refrigerants. As a result, it is in stable demand as a well-balanced CFC gas among the refrigerants currently available.

On the other hand, R32 is flammable, so it is important to use it properly. MEMS sensors are therefore utilized to ensure safe use and control, and are used to enhance the reliability of air conditioners and air conditioning systems that use refrigerants.

The Future of Energy Saving and MEMS

Energy saving is now a global environmental issue. All member countries of the United Nations have signed and participated in the United Nations Framework Convention on Climate Change (UNFCCC), adopted in 1992, and each country is working on various measures.

Energy-saving efforts in housing and construction are progressing, especially in developed countries, and energy-saving standards have been established for facilities that perform heating, cooling, ventilation, hot water supply, and lighting. Therefore, in order to comply with these standards in each country, they are being applied to new houses, and existing houses with low energy-saving performance are being renovated.

Emerging countries are also taking various energy-saving measures. In January 2022, China announced its 14th Five-Year Plan, which includes major targets for energy saving and carbon emission reduction, as well as 10 priority projects. India has been working on energy saving from an early stage, with the enactment of the Energy Conservation Act in 2001 and the implementation of an energy saving labeling system for household electrical products in May 2006.

As described above, efforts to achieve decarbonization and energy saving are steadily expanding, although policies differ from country to country and region to region.

One of the reasons MEMS technology is attracting attention for energy saving is its unrivaled capability to enable miniaturization.

By converting conventional HVAC sensors to MEMS, even small parts can be equipped with various functions, and the smaller size of the device itself helps to reduce the amount of power used. Thus, further use of MEMS technology is expected to help solve the difficult problem of energy saving.

1. The Montreal Protocol required the phasing out of HCFCs among developed countries by 2020.
2. The Montreal Protocol mandated the reduction of HFCs among developed countries beginning in 2019.