The internet of things (IoT) is a system consisting of computing, mechanical, and electronic devices, which are having ability to transfer data in network without human interaction. The sensors used in IoT collect and transfer the data to the cloud, which is further processed using software to perform an action. The IoT is one of the fastest growing industries, and in recent years, it is most widely used in HVAC systems in residential and commercial applications to reduce the energy consumption as building consumes by approximately 40% of total energy. The IoT reduces the energy consumption of the building by optimizing the process variables of HVAC system components, increases life of system components, enhances the comfort of the occupants, and provides remote control of the system. However, there are challenges in data security and privacy, and also there is a lack of IoT platforms specifically oriented towards the proper processing, management, and analysis of such large and diverse data.
TopIntroduction
The heating, ventilation, and air conditioning (HVAC) system is the mechanical air handling systems used in building to provide necessary indoor air quality by controlling temperature, humidity, purity, velocity etc. by conditioning the air to provide comfort indoor space for the occupants. The indoor air is replaced with outdoor air at regular intervals to dilute and remove contaminants and to remove odour. The infiltration or exfiltration may affect the quality of the indoor air. The important parts of the HVAC are chiller, air handling unit, air distribution system, air exhaust system etc. Figure 1 shows the schematic of the HVAC system. The chiller produces the cooling effect and it is transferred to the water. This chilled water is circulated to the air handling unit (AHU) using a pump. The room air is drawn to the AHU and is filtered to remove dusts, mold etc., cooled using cooling coil, humidified or dehumidified and finally circulated to the room. The humidifier and dehumidifier control the humidity of the air. In winter, heating coil is used to heat the air. Some percentage of room air is replaced with the outdoor air to control the carbon dioxide level. The air distribution system consists of fans, filters, dampers, ductwork etc. supplies the conditioned air to the room to maintain required indoor conditions. The return air system draws the room air and is send it to the AHU for conditioning. This return air is mixed with outdoor air and is re-conditioned using filter, cooling coil, humidifier / dehumidifier and re-circulated to the indoor space. Figure 2 shows the schematic of the AHU.
Figure 1. Schematic of the HVAC system
Figure 2. Schematic of the AHU system
TopBackground
The figure 3 shows the energy consumption by different equipment used in commercial building. It shows that the major energy is consumed for space heating, ventilation, space cooling and lighting (Bawaneh et al., 2019). The HVAC system is available in different capacity and selection is based on application and building design. It consumes 40 to 50% of the total energy consumed by the building. The HVAC systems are most widely used in commercial building such as IT Park, hotels, resorts, office, malls, airports, railway station, educational institutions, hospitals, etc.
Figure 3. Energy consumption in commercial building
The climate condition, characteristics of building and occupancy rate and patterns significantly affects the HVAC energy demand. The HVAC systems consume major amount of the building energy in developed countries like, USA, Canada, European Union, Australia etc. The HVAC demand of the world is increasing exponentially, which may cause serious strains on electrical grids. The increase in HVAC demand is higher in developing nations such as India and China and countries with hot climate such as Middle East countries. The International Energy Agency (IEA) report estimated that the world energy demand from HVAC systems may triple by 2050. The commercial refrigeration systems consume about 40 to 60% of the energy consumed in the supermarkets. Hence the HVAC and refrigeration systems may cause strain on electrical grids and IEA suggest new efficiency standard, efficiency improvement etc. to reduce the energy demand. The increase in energy demand adds new power plants which increases the CO2 emission. Hence it is necessary to introduce a new energy efficient technology to reduce the energy consumption and also to augment indoor comfort of the building occupants (International Energy Agency, 2020). Figure 4 shows the building energy consumption in developed and developing countries such as USA, EU and China. From this figure, we observe that the space cooling and space heating and ventilation consumes more than 50% of the building energy.
Figure 4. Building energy consumption pattern in different countries