**2. Development of integrated sunshading board and Building-Integrated Photovoltaic (BIPV)**

Previous research results published in literature [6–8] shows that if based on the total CO2 emission from a building with 50-year life cycle, about 80% of CO2 emission is caused by the air conditioning. The energy saving regulations enforced in Taiwan stipulated that the building shell energy consumption index be used for designing an energy-saving building. In other words, the annual thermal loadings is the thermal loading for providing air conditioning to maintain a healthy and comfortable room; the loading is based on the outdoor thermal environment adjacent to windows, walls, and wall openings.

The thermal flow caused by "difference between outdoor and indoor temperatures" and "solar radiation" is the major factor causing air conditioning energy loadings. Hence, the technology of insulating the building and shading the solar radiation is an important factor for designing the energy-saving features of a building. The effectiveness of solar panels is affected by environmental factors such as solar illumination and temperature, among many others, which affect the voltage and current of the electricity produced, causing unusual movement of Flyback Converters.

A solar panel combined with a shading board is proposed in this research to increase the building shading effect so that the cost-effectiveness of the solar panel can be augmented. A current convertor to convert the produced DC (direct current) into AC (alternate current) and electricity storage to overcome the inherited problem of unstable energy source for solar panels are also integrated into the BIPV building in order to raise the cost-effectiveness of the proposed system.

#### **2.1. Design of external shading**

In recent years, the booming semi-conductor industry had led to rapid advances in manufac‐ turing and implementing solar energy projects more cost effectively. Hence, solar energy is

In Taiwan, central air conditioning systems are used in large buildings that accommodate offices, hotels, department stores and hospitals. These buildings, which are considered as "airconditioned buildings", have fixed office hours, similar occupants and application modes, and hence comparable heat generated from illumination and occupants. Additionally, these buildings adopt a glass shell to shield the structure so that natural lighting is available during

The expected benefits of using solar panels on buildings include lowering building costs, reducing energy consumption, and providing a more comfortable indoor environment. The greenhouse effectiveness in glass buildings is also applied in cold zones for saving heating energy. Additionally, large glass windows also provide excellent views for occupants to assist in improving their moods and work efficiency. Hence, in recent years, buildings covered in glass panels are becoming popular in the US and some European nations. Influenced by the global trend, the architecture in Taiwan has adopted this type of buildings. However, when irradiated under direct sunlight, this type of building is considered to be badly insulated, so that a huge quantity of energy is needed to provide adequate air conditioning for resisting the

More intensive solar radiation causes either higher indoor temperatures, heavier loading on the air-conditioning unit, or higher consumption of electric energy. If solar energy is available, more intensive solar rationing means that more electricity can be generated. Hence, if the building is covered with solar panels instead of glass windows, the incoming solar radiation can be intercepted for generating electricity that will provide building cooling in addition to reducing the indoor air temperature caused by direct sunshine. The excess electricity can be sold back to the power company to offset the peak loading period. Hence, in this research, the energy audit for the buildings covered with glass panels and cooled with central air condi‐ tioners will be carried out for developing three types of "integrated solar panel" systems.

In this research, the results of analysing indigenous climates and examining building materials are used to propose the replacement of conventional glass plate by solar photoelectric panels to be an integrated part of the building shell proposed as the BIPV (Building-Integrated Photovoltaic) system in building architecture. Results of laboratory studies proved that in addition to providing electrical energy to the building, the BIPV building shell is also effective

The BIPV system proposed in this research will greatly alleviate the electricity burden during peak hours; its application will promote the development of sustainable energy sources. Comparisons of these solar panels to be used on buildings will be conducted based on their material, angle, temperature, and panel clarity. The results will be used to access the actual

cost-effectiveness of installing and using these solar panels on existing buildings.

expected to be an important and a major source of energy in the future.

daytime for saving electricity.

144 Solar Radiation Applications

outdoor heat loadings.

in thermally shielding and isolating the building.

Taiwan is located in subtropical region; research results indicate that the major factors affecting the air conditioning energy consumption for buildings in the hot and humid environment are the "percentage of window opening" and "window shielding factor" About 62–85% of the building's air conditioning energy is affected by these two factors whereas only 10–15% depends on the orientation of the building in question. Among these factors, the "opening percentage" is the most influential factor; buildings with higher opening percentage will waste more energy on air conditioning.

Regardless of the type of glass used for windows, a 1% increase of the glass window area will cause the energy consumption to rise by 1.0%. In contrast, the "window shielding factor" will save energy consumed for air conditioning in addition to preventing reflective light to ensure good natural lighting and views. The studies in this research were conducted in South Taiwan. Based on local climatic and geographic conditions, and incident angle of solar radiation, the outside window shielding system will be designed as blinds with 1:4 horizontal to vertical ratio (the horizontal shielding depth is 60 cm for a 240 cm French window) to evaluate its thermal insulating efficient.

#### **2.2. Solar photoelectrical system**

The integrated system consists of several modules: including the solar electricity-generating module, an integrated parallel connection module to connect to the municipal power system, an emergency power supply module to convert direct and alternate currents, and a battery module to store excess energy produced during the daytime.

#### *2.2.1. Solar photoelectrical system*

The basic principle of solar electricity generation is to convert solar light with wavelengths between 0.7 to 0.9 micrometer irradiating on a semiconductor. Inside the semiconductor, negatively charged electron and positively charged electron holes will be generated and accumulated at the P-type and N-type layer regions, respectively, thus producing an electro‐ motive difference depending on their unique characteristics. If connected to an external loading, the semiconductor cell produces electricity that can be used for a variety application in the building

#### *2.2.2. Integrated parallel connection to municipal power system and exchanger to provide emergency direct and alternate electric currents*

The electricity produced by solar panels and batteries is direct current (DC) whereas the general appliances use alternate current (DC). Hence, the solar generated DC must be con‐ verted into AC with an electric converter so that the electric energy can be widely supplied to household appliances. Additionally, solar electricity generation depends on the solar intensity and angle that the output electrical current and voltage are unstable. If used as an independent electric source, the energy system lacks stability and will not provide a reliable source of energy. Hence, a converter must be used to change the pattern of electricity; in addition to converting the solar generated DC into AC, the solar electricity generation module will be connected to municipal power system to maintain a steady supply of electricity. When the solar energy becomes insufficient, the municipal power system will kick in to provide the needed electricity. If the solar energy is greater than the loading, the excess electricity can be sent back to other consumers through the municipal power system. This arrangement will greatly elevate the stability of solar energy generation system to fully extend it cost-effective‐ ness.

#### *2.2.3. Battery module*

When the electric system is operated steadily, changes in the solar electricity generated and the system operation in response to variations of external conditions will be compensated by using the battery module. If the solar system produces more electricity than is needed, the excess electricity will charge the battery model, or it will be sent back to the municipal power system.

When the solar electricity is insufficient (such as at night) to meet the building's demands, the electricity stored in the battery module will supply the needed power before obtaining power from the municipal system. Thus, the battery module will allow the solar system to be flexible in response to various conditions. Additionally, when the solar power system malfunctions, or the electrical voltage becomes 10% higher or 15% lower than the normal level, the battery can temporarily kick in to make the adjustment so that the solar power system combined with the battery module will depend less on the municipal system to provide steady electricity to meet the loadings.

#### **2.3. Integrated Photovoltaic (BIPV)**

**2.2. Solar photoelectrical system**

146 Solar Radiation Applications

*2.2.1. Solar photoelectrical system*

*direct and alternate electric currents*

in the building

ness.

system.

*2.2.3. Battery module*

module to store excess energy produced during the daytime.

The integrated system consists of several modules: including the solar electricity-generating module, an integrated parallel connection module to connect to the municipal power system, an emergency power supply module to convert direct and alternate currents, and a battery

The basic principle of solar electricity generation is to convert solar light with wavelengths between 0.7 to 0.9 micrometer irradiating on a semiconductor. Inside the semiconductor, negatively charged electron and positively charged electron holes will be generated and accumulated at the P-type and N-type layer regions, respectively, thus producing an electro‐ motive difference depending on their unique characteristics. If connected to an external loading, the semiconductor cell produces electricity that can be used for a variety application

*2.2.2. Integrated parallel connection to municipal power system and exchanger to provide emergency*

The electricity produced by solar panels and batteries is direct current (DC) whereas the general appliances use alternate current (DC). Hence, the solar generated DC must be con‐ verted into AC with an electric converter so that the electric energy can be widely supplied to household appliances. Additionally, solar electricity generation depends on the solar intensity and angle that the output electrical current and voltage are unstable. If used as an independent electric source, the energy system lacks stability and will not provide a reliable source of energy. Hence, a converter must be used to change the pattern of electricity; in addition to converting the solar generated DC into AC, the solar electricity generation module will be connected to municipal power system to maintain a steady supply of electricity. When the solar energy becomes insufficient, the municipal power system will kick in to provide the needed electricity. If the solar energy is greater than the loading, the excess electricity can be sent back to other consumers through the municipal power system. This arrangement will greatly elevate the stability of solar energy generation system to fully extend it cost-effective‐

When the electric system is operated steadily, changes in the solar electricity generated and the system operation in response to variations of external conditions will be compensated by using the battery module. If the solar system produces more electricity than is needed, the excess electricity will charge the battery model, or it will be sent back to the municipal power

When the solar electricity is insufficient (such as at night) to meet the building's demands, the electricity stored in the battery module will supply the needed power before obtaining power from the municipal system. Thus, the battery module will allow the solar system to be flexible The integrated photoelectrical solar panels used in this experiment have 30kW capacity consisting of 8.58kW, 8.82kW, and 12.6kW panels. Figure 1 shows the system (System I) equipped with multiple crystal silica arrays.

**Figure 1.** Integrated photoelectrical solar panel System I of 8.58kW

Figure 2 shows the system (System II) equipped with multiple silica and single silica solar energy photoelectrical panels.

**Figure 2.** Integrated photoelectrical solar panel System II of 8.82kW

Figure 3 shows the system (System III) with single silica solar photoelectrical panels only installed.

In each system, the panel faces south, and is 25° inclined that can be manually adjusted 10° up and down. These systems were used to investigate the influence of solar panel material, angle of inclination, ambient temperature and panel clarity on the effectiveness of solar energy generation.

**Figure 3.** Integrated photoelectrical solar panel System III of 12.6kW

Figure 2 shows the system (System II) equipped with multiple silica and single silica solar

Battery

Battery

Charge discharge electricity controller

Charge discharge electricity controller

Charge discharge electricity controller

RS 485

INVERTER Output 3kW

INVERTER Output 3kW

INVERTER Output 3kW

, , kW, kWh

receiving and carrying on load of A

A

TS gird 380V

A

C or 220V

A

C

TS or series

connection with

Using RS 485 interface transmission to search and collect data for analysing and comparing

Computer

Figure 3 shows the system (System III) with single silica solar photoelectrical panels only

In each system, the panel faces south, and is 25° inclined that can be manually adjusted 10° up and down. These systems were used to investigate the influence of solar panel material, angle of inclination, ambient temperature and panel clarity on the effectiveness of solar energy

Battery

interface transmission

energy photoelectrical panels.

Polycrystalline silicon solar

70 Watt-7 string of 6 abreast of 2.94 kW- total 42 slices

Polycrystalline silicon solar

Monocrystalline silicon solar

70 Watt-7 string of 6 abreast of 0.42 kW- total 6 slices Total 2.94kW

Monocrystalline silicon solar

70 Watt-7 string of 6 abreast of 2.94 kW- total 42 slices

energy array

148 Solar Radiation Applications

energy array 70 Watt -2.52kW -total 36 slices

Energy array

Legend

installed.

generation.

energy array

Photoelectric system route

Information transmission route

**Figure 2.** Integrated photoelectrical solar panel System II of 8.82kW
