**3.1 High-efficiency lighting**

In order to reduce lighting energy consumption, it is important to actively use daylighting, for example, by adopting natural lighting techniques. At the same time, it is possible to reduce energy consumption while providing an appropriate lighting environment (illuminance, etc.) by using more efficient lighting equipment such as LED lighting to compensate for the lack of brightness from the use of daylight alone. In addition, by properly controlling such lighting equipment, even higher energysaving effects can be expected.

**Figure 11** shows the examples of lighting control by human sensors and wireless remote thermosat, task-ambient lighting control, and a combination of these controls.

As shown in **Figure 11** on the left, this control uses human sensors to detect the presence or absence of people and turns on or off the air conditioning and lighting. In addition, a remote thermostat that accurately measures the temperature of the area where the person is and efficiently controls the air conditioning.

As shown in **Figure 11** on the right, the ceiling lighting should function as ambient lighting for room ambiance, while desk brightness is adequately provided by the task lighting for work at hand. This is the most effective method for reducing lighting power.

For the high-efficiency lighting utilization in Japan, a study showed that when the high-efficiency lighting fixtures and lighting control systems have been introduced in an office buildings of Japan, the electricity consumption savings of 30 to 50% per year can be expected, and a significant energy savings can be achieved without degrading the quality of lighting [17].

**Figure 11.**

*Example of optimal lighting system control in an office building.*

## **3.2 High-efficiency air conditioning**

In order to reduce the energy consumption of air conditioning, it is important to control the load of heating and cooling by adopting passive technologies such as external skin insulation and solar radiation shielding that are elaborated in Section 2. However, since it is often difficult to maintain a comfortable indoor environment with these measures alone, it is important to reduce energy consumption while maintaining a comfortable thermal environment by using an air-conditioning system with higher efficiency and appropriate control to compensate for this. In a typical office building, energy consumption by the air-conditioning system accounts for the largest percentage of the total energy consumption, and the importance of reducing it is very high.

Air-conditioning systems can be broadly divided into central heat source systems and individual distributed heat source systems. In the central heat source system (as shown in **Figure 12**), heat sources are concentrated in machine rooms, etc., and cold and hot water is pumped to the air conditioner for air conditioning. In the individual distributed heat source system (as shown in **Figure 13**), heat sources are distributed and transported using refrigerant piping to air condition for each floor or zone. Both the central heat source system and the individual distributed heat source system consist of "heat source equipment," "heat transfer equipment," and "air conditioner equipment". In the case of a distributed heat source system, the heat source and air-conditioning equipment are integrated into a single unit. Therefore, energy consumption can be reduced by adopting more efficient equipment and implementing appropriate controls for each facility.

In general, the central heat source system is used in large buildings, while the individual distributed heat source system is used in many small buildings.

Measures to reduce the energy consumption of air-conditioning equipment include air-conditioning systems that separate latent heat from sensible heat to adjust

## *Introduction of ZEB Technology in Japan DOI: http://dx.doi.org/10.5772/intechopen.101464*

#### **Figure 12.**

*Example of the central heat source system.*

**Figure 13.** *Example of the individual distributed heat source system.*

#### **Figure 14.**

*Conceptual diagram of radiant heating and cooling air-conditioning systems.*

temperature and humidity separately, and new air-conditioning systems such as radiant heating and cooling air-conditioning systems (**Figure 14**) that focus not only on temperature and humidity but also on the comfort felt by people.

A radiant heating and cooling system is a system that uses the effect of "radiation (the transfer of heat from a higher to a lower temperature without the use of materials)" to adjust the experience of building users, thereby easing the indoor set temperature and saving energy. Compared to conventional air conditioner systems, this system is more comfortable and less uncomfortable due to airflow drafts and uneven temperatures.

For the high-efficiency air-conditioning system, a study showed that a kind of developed high-efficiency air-conditioning control system with promotion of energy-saving behaviors were installed in may stores of Japan [18]. The "promotion of energy-saving behavior" supports the voluntary establishment of employee behavior by proposing optimal energy-saving behavior for each store based on AI power prediction and displaying screens using nudge theory *via* tablets distributed to stores. The high-efficiency air-conditioning control system suppresses demand based on AI power prediction and operates the air-conditioning compressor at a high COP load rang, and achieves energy savings of more than 3% through behavioral promotion and more than 4% through air-conditioning control.
