A building integrated energy system (photovoltaic (PV) and fuel cell (FC)) is proposed for assessment of the energy self-sufficiency rate in five cities of Mie prefecture in Japan. In this work, it is considered that the electricity requirement of the building is provided by the building integrated photovoltaic (BIPV) system and the gap between the energy demand and BIPV supply is fulfilled by the FC. The FC is powered by the electrolytic H2 produced from the surplus power of PV. A design study of using the proposed system in five cities in Mie prefecture, which are in center part of Japan, has been performed. It has been observed that the monthly power production from BIPV is higher in spring and summer, while it is lower in autumn and winter at all considered locations. The self-sufficiency rate of the FC system is higher with decreasing households’ number and it has been observed that the 12 households are more suitable for full cover of the electricity demand by the combined system of PV and FC. The relationship between the households’ number and self-sufficiency rate of the FC system per solar PV installation area can be expressed by exponential curve. The coefficient of the exponential curve can predict the suitable city for the BIPV system with FC system utilizing electrolytic H2 generated by using excess energy from the PV system.
Fossil fuel reserves are limited and intensive burning of hydro-carbon based fuel sources is impacting on global climate. Renewable energy sources such as wind, solar photovoltaic (PV), solar thermal, geothermal, bio-energy are drawing attention as alternative environment-friendly energy sources [
Integrating renewable energy sources into the existing energy system network is an effective approach in the development of net zero-energy buildings’ built environment, it is challenging to integrate intelligently renewable energy sources and distributed generators as the existing building infrastructures are not designed to accept them into the power system infrastructure [
Integrating/installing solar panels on the roof and/or side wall of the building is a typical way to make the building energy self-sufficient. Such kind of building integrated PV systems (BIPV) has been studied by many researchers [
Due to solar energy’s intermittent nature, the BIPV system normally requires a sort of energy storage system and/or grid-connected mechanism [
In this paper, a design study has been performed on a proposed BIPV system with utilization of stored energy in the form of electrolytic H2 through FC during the power production from the PV system. The proposed BIPV system consists of the solar PV array, water electrolyzer and fuel cell (FC). The H2 required by the FC is provided from the stored electrolytic H2 produced using the surplus power of the PV. The FC would therefore be able to buffer the intermittency (partly) between the building electricity demand (by the building) and the PV system. The BIPV power productions at the five cities in Mie prefecture, Japan have been evaluated using the meteorological data of the project “PV300” (period from August, 2013 to July, 2014 [
The building model, used in the design study, is 10 m width, 40 m length and 40 m height (=10 stories) [
The power generated by PV system is calculated by using the following equation [
where EPV is hourly electric power of PV system (kWh), H is hourly amount of solar radiation (kWh/m2), K is power generation loss factor (−), P is system capacity of PV (kW), 1 is solar radiation under standard state (AM1.5, hourly solar radiation: 1 kWh/m2, module temperature: 25 degree Celsius) (kW/m2). The instantaneous solar radiation data by 10 sec of the reference [
In this study, the high-performance PV P250a Plus produced by Panasonic has been considered. This module has conversion efficiency and maximum power rating per module is 19.5% and 250 W [
where Kp is power conversion efficiency of power conditioner (−), Km is correction factor decided by module temperature (−), Ki is power generation loss by interconnecting and dirty of module surface (−). In this study, Kp and Ki are set at 0.945 and 0.95, respectively. Kp is assumed by referring to the performance of commercial power conditioning device VBPC259B3 manufactured by Panasonic [
where Tm is PV module temperature (degree Celsius), Ts is temperature under standard test condition (=25 degree Celsius) (degree Celsius), C is temperature correction factor which is 0.35 [
where Ta is ambient air temperature (degree Celsius), Um is wind velocity over module of PV (m/s). In this equation, the convection heat transfer by wind around the PV module is considered.
The meteorological data, such as solar radiation, the ambient air temperature, and wind velocity of some cities in Japan have been taken from the data base of the project “PV300” during the period from August, 2013 to July, 2014 [
In this design study, it has been assumed that the surplus power generated by the PV system over the electricity demand of households [
Year | Month | Day | Hour | Min | Sec | Amount of horizontal solar radiation (kW/m2) | Air temperature (degree Celsius) |
---|---|---|---|---|---|---|---|
2013 | 8 | 1 | 9 | 0 | 0 | 0.1179 | 30.7 |
2013 | 8 | 1 | 9 | 0 | 10 | 0.1158 | 30.8 |
2013 | 8 | 1 | 9 | 0 | 20 | 0.1115 | 30.7 |
2013 | 8 | 1 | 9 | 0 | 30 | 0.1130 | 30.8 |
2013 | 8 | 1 | 9 | 0 | 40 | 0.1150 | 31.0 |
2013 | 8 | 1 | 9 | 0 | 50 | 0.1120 | 30.9 |
2013 | 8 | 1 | 9 | 1 | 0 | 0.1107 | 30.8 |
2013 | 8 | 1 | 9 | 1 | 10 | 0.1123 | 30.8 |
2013 | 8 | 1 | 9 | 1 | 20 | 0.1166 | 31.0 |
2013 | 8 | 1 | 9 | 1 | 30 | 0.1179 | 30.9 |
2013 | 8 | 1 | 9 | 1 | 40 | 0.1183 | 30.8 |
2013 | 8 | 1 | 9 | 1 | 50 | 0.1194 | 30.8 |
2013 | 8 | 1 | 9 | 2 | 0 | 0.1229 | 30.8 |
2013 | 8 | 1 | 9 | 2 | 10 | 0.1249 | 30.6 |
2013 | 8 | 1 | 9 | 2 | 20 | 0.1267 | 30.5 |
2013 | 8 | 1 | 9 | 2 | 30 | 0.1270 | 30.3 |
2013 | 8 | 1 | 9 | 2 | 40 | 0.1262 | 30.1 |
2013 | 8 | 1 | 9 | 2 | 50 | 0.1258 | 30.1 |
2013 | 8 | 1 | 9 | 3 | 0 | 0.1298 | 30.4 |
H2 could be produced by the surplus power generated from the PV system is calculated by the following equation [
where
It has been assumed that the H2 produced by the electolyzer would be used to generate power through a polymer electrolyte fuel cell (PEFC) system [
where
In this study, a monthly self-sufficiency rate of the proposed combination system consisting of the PV and FC has been investigated for Tsu (Latitude: 34.43˚N, Longitude: 136.30˚E), Yokkaichi (Latitude: 34.57˚N, Longitude: 136.37˚E), Kuwana (Latitude: 35.03˚N, Longitude: 136.41˚E), Ise (Latitude: 34.29˚N, Longitude: 136.42˚E) and Owase (Latitude: 34.04˚N, Longitude: 136.11˚E). They are the main cities in Mie prefecture, Japan. The self-sufficiency rate is defined as the power supplied (from the combined PV and FC system) to the electricity demand of the households living in the building. The hourly time change in the self-sufficiency rate in the day, when the daily mean amount of horizontal solar radiation per month has been obtained and estimated.
As described in earlier sections, this study has investigated the power production from the PV system using the meteorological data base of PV300 [
As an example,
Time (h) | Aug. 2013 | Sep. 2013 | Oct. 2013 | Nov. 2013 | Dec. 2013 | Jan. 2014 | Feb. 2014 | Mar. 2014 | Apr. 2014 | May 2014 | Jun. 2014 | Jul. 2014 |
---|---|---|---|---|---|---|---|---|---|---|---|---|
0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
2 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
3 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
4 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
5 | 2 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 2 | 3 | 4 |
6 | 6 | 2 | 4 | 0 | 0 | 0 | 1 | 3 | 2 | 9 | 7 | 11 |
7 | 24 | 14 | 16 | 6 | 2 | 1 | 5 | 9 | 7 | 19 | 16 | 23 |
8 | 36 | 33 | 29 | 18 | 10 | 14 | 15 | 19 | 23 | 42 | 26 | 24 |
9 | 50 | 47 | 33 | 25 | 15 | 28 | 22 | 17 | 36 | 48 | 46 | 29 |
10 | 57 | 49 | 28 | 30 | 28 | 24 | 37 | 21 | 47 | 54 | 49 | 54 |
11 | 61 | 37 | 29 | 29 | 35 | 35 | 35 | 36 | 53 | 51 | 52 | 58 |
12 | 59 | 34 | 33 | 30 | 31 | 36 | 40 | 48 | 52 | 49 | 43 | 31 |
13 | 42 | 21 | 18 | 28 | 27 | 18 | 29 | 51 | 52 | 53 | 39 | 21 |
14 | 15 | 17 | 12 | 19 | 15 | 19 | 21 | 36 | 47 | 28 | 26 | 44 |
15 | 3 | 16 | 5 | 9 | 5 | 15 | 20 | 29 | 24 | 23 | 18 | 16 |
16 | 4 | 16 | 2 | 1 | 1 | 4 | 8 | 11 | 13 | 15 | 10 | 11 |
17 | 2 | 3 | 0 | 0 | 0 | 0 | 2 | 2 | 4 | 7 | 4 | 8 |
18 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 3 |
19 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
20 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
21 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
22 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
23 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
Total | 362 | 291 | 210 | 197 | 170 | 194 | 235 | 284 | 360 | 400 | 340 | 337 |
City | Aug. 2013 | Sep. 2013 | Oct. 2013 | Nov. 2013 | Dec. 2013 | Jan. 2014 | Feb. 2014 | Mar. 2014 | Apr. 2014 | May 2014 | Jun. 2014 | Jul. 2014 |
---|---|---|---|---|---|---|---|---|---|---|---|---|
Tsu | 11.2 | 8.74 | 6.50 | 5.90 | 5.27 | 6.02 | 6.59 | 8.80 | 10.8 | 12.4 | 10.2 | 10.5 |
Yokkaichi | 11.7 | 8.37 | 5.04 | 4.44 | 4.19 | 5.58 | 6.39 | 8.20 | 7.82 | 9.65 | 9.93 | 7.77 |
Kuwana | 10.8 | 7.92 | 6.36 | 5.00 | 4.04 | 6.43 | 7.01 | 8.34 | 9.88 | 9.16 | 10.3 | 7.91 |
Ise | 8.03 | 7.10 | 5.00 | 5.87 | 4.66 | 4.05 | 4.13 | 7.81 | 6.92 | 9.95 | 9.01 | 7.79 |
Owase | 10.7 | 7.14 | 3.27 | 6.93 | 5.67 | 7.07 | 4.85 | 5.43 | 9.42 | 13.3 | 7.84 | 5.89 |
Time (h) | Aug. 2013 | Sep. 2013 | Oct. 2013 | Nov. 2013 | Dec. 2013 | Jan. 2014 | Feb. 2014 | Mar. 2014 | Apr. 2014 | May 2014 | Jun. 2014 | Jul. 2014 |
---|---|---|---|---|---|---|---|---|---|---|---|---|
0 | 3 | 3 | 3 | 3 | 4 | 4 | 4 | 4 | 4 | 3 | 2 | 3 |
1 | 3 | 3 | 3 | 3 | 3 | 4 | 4 | 4 | 4 | 3 | 2 | 3 |
2 | 3 | 3 | 3 | 3 | 3 | 4 | 4 | 3 | 4 | 3 | 2 | 3 |
3 | 3 | 3 | 3 | 3 | 3 | 4 | 4 | 3 | 4 | 3 | 2 | 3 |
4 | 2 | 2 | 3 | 3 | 3 | 4 | 4 | 4 | 4 | 3 | 2 | 2 |
5 | 2 | 2 | 2 | 2 | 3 | 4 | 4 | 4 | 2 | 2 | 2 | 2 |
6 | 7 | 6 | 7 | 7 | 7 | 8 | 8 | 7 | 8 | 7 | 5 | 6 |
7 | 9 | 8 | 8 | 8 | 10 | 13 | 12 | 11 | 9 | 8 | 7 | 8 |
8 | 10 | 9 | 8 | 8 | 11 | 14 | 13 | 12 | 9 | 8 | 8 | 9 |
9 | 9 | 8 | 8 | 8 | 10 | 13 | 12 | 11 | 9 | 8 | 7 | 8 |
10 | 9 | 8 | 8 | 8 | 10 | 12 | 12 | 11 | 9 | 8 | 7 | 8 |
11 | 9 | 8 | 8 | 8 | 10 | 12 | 12 | 11 | 9 | 8 | 7 | 8 |
12 | 10 | 9 | 8 | 8 | 10 | 12 | 12 | 11 | 9 | 8 | 7 | 8 |
13 | 11 | 10 | 8 | 8 | 10 | 12 | 12 | 11 | 9 | 8 | 8 | 9 |
14 | 11 | 10 | 8 | 8 | 10 | 12 | 12 | 11 | 9 | 8 | 8 | 9 |
15 | 10 | 9 | 8 | 8 | 10 | 12 | 12 | 11 | 9 | 8 | 7 | 9 |
16 | 10 | 9 | 8 | 8 | 10 | 12 | 12 | 11 | 9 | 8 | 7 | 8 |
17 | 10 | 9 | 8 | 8 | 14 | 17 | 16 | 15 | 9 | 8 | 7 | 8 |
18 | 14 | 13 | 13 | 13 | 14 | 17 | 16 | 15 | 15 | 13 | 11 | 12 |
19 | 25 | 23 | 19 | 19 | 16 | 19 | 18 | 17 | 22 | 19 | 19 | 22 |
20 | 25 | 23 | 18 | 19 | 15 | 18 | 17 | 16 | 21 | 19 | 19 | 22 |
21 | 24 | 22 | 16 | 17 | 14 | 17 | 16 | 15 | 19 | 17 | 18 | 21 |
22 | 20 | 18 | 15 | 16 | 12 | 15 | 14 | 13 | 18 | 16 | 15 | 17 |
23 | 17 | 15 | 15 | 15 | 9 | 11 | 11 | 10 | 17 | 15 | 12 | 14 |
Total | 257 | 232 | 208 | 214 | 220 | 272 | 259 | 240 | 237 | 211 | 192 | 221 |
summer and winter, while it is lower in spring and autumn. The data shown in
Time (h) | Aug. 2013 | Sep. 2013 | Oct. 2013 | Nov. 2013 | Dec. 2013 | Jan. 2014 | Feb. 2014 | Mar. 2014 | Apr. 2014 | May 2014 | Jun. 2014 | Jul. 2014 |
---|---|---|---|---|---|---|---|---|---|---|---|---|
0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
2 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
3 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
4 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
5 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
6 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 |
7 | 3 | 1 | 2 | 0 | 0 | 0 | 0 | 0 | 0 | 2 | 2 | 3 |
8 | 5 | 5 | 4 | 2 | 0 | 0 | 0 | 1 | 3 | 7 | 4 | 3 |
9 | 9 | 8 | 5 | 4 | 1 | 3 | 2 | 1 | 6 | 8 | 8 | 4 |
10 | 10 | 9 | 4 | 5 | 4 | 2 | 5 | 2 | 8 | 10 | 9 | 10 |
11 | 11 | 6 | 4 | 4 | 5 | 5 | 5 | 5 | 9 | 9 | 9 | 10 |
12 | 10 | 5 | 5 | 5 | 4 | 5 | 6 | 5 | 9 | 9 | 7 | 5 |
13 | 7 | 2 | 2 | 4 | 4 | 1 | 4 | 8 | 9 | 9 | 6 | 3 |
14 | 1 | 2 | 1 | 2 | 1 | 1 | 2 | 8 | 8 | 4 | 4 | 7 |
15 | 0 | 1 | 0 | 0 | 0 | 0 | 2 | 5 | 3 | 3 | 2 | 1 |
16 | 0 | 2 | 0 | 0 | 0 | 0 | 0 | 4 | 1 | 1 | 1 | 0 |
17 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
18 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
19 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
20 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
21 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
22 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
23 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
Total | 56 | 41 | 29 | 26 | 19 | 18 | 26 | 36 | 56 | 64 | 53 | 49 |
City | Aug. 2013 | Sep. 2013 | Oct. 2013 | Nov. 2013 | Dec. 2013 | Jan. 2014 | Feb. 2014 | Mar. 2014 | Apr. 2014 | May 2014 | Jun. 2014 | Jul. 2014 |
---|---|---|---|---|---|---|---|---|---|---|---|---|
Tsu | 1.73 | 1.24 | 0.884 | 0.785 | 0.592 | 0.573 | 0.729 | 1.10 | 1.68 | 1.98 | 1.60 | 1.52 |
Yokkaichi | 1.84 | 1.22 | 0.609 | 0.532 | 0.441 | 0.552 | 0.731 | 1.03 | 1.10 | 1.52 | 1.59 | 1.02 |
Kuwana | 1.66 | 1.12 | 0.878 | 0.646 | 0.410 | 0.724 | 0.858 | 1.05 | 1.49 | 1.42 | 1.67 | 1.05 |
Ise | 1.11 | 0.957 | 0.608 | 0.818 | 0.508 | 0.328 | 0.330 | 0.961 | 0.884 | 1.53 | 1.40 | 1.04 |
Owase | 1.56 | 0.902 | 0.292 | 0.991 | 0.684 | 0.798 | 0.429 | 0.436 | 1.36 | 2.17 | 1.12 | 0.576 |
calculated by dividing the power produced by the FC system by the electricity demand, which is not covered by the PV system. If the self-sufficiency rate of the FC system is over 100%, then the proposed BIPV system with the FC system utilizing electrolytic H2 generated by water electrolysis can cover the electricity demand of households living in the building.
According to
It has been seen from
The households number is changed to investigate the proper households number per same installment area of solar array on the roof/top of building. Figures 2-4 have shown the monthly self-sufficiency rate of FC system assumed to be installed in Tsu, Yokkaichi, Kuwana, Ise and Owase for 20, 16 and 12 households cases, where the stories of buildings are 5, 4 and 3, respectively. These figures are shown to investigate the seasonal and locational characteristics under different households conditions.
It has been observed through Figures 2-4, the self-sufficiency rate of FC system is higher with decreasing households number, resulting that the self-suffi- ciency rate of FC system which is over 100% can be seen in spring and summer.
The annual self-sufficiency rate of the FC system assumed to be installed in Tsu, Yokkaichi, Kuwana, Ise and Owase for 20 households design case are 74%, 60%, 63%, 52% and 61%, respectively. The annual self-sufficiency rate of the FC system assumed to be installed in Tsu, Yokkaichi, Kuwana, Ise and Owase for 16 households design case are 98%, 79%, 83%, 69% and 81%, respectively. The annual self-sufficiency rate of the FC system assumed to be installed in Tsu, Yokkaichi, Kuwana, Ise and Owase for 12 households design case are 138%, 111%, 117%, 98% and 115%, respectively. From these results, 12 households are more suitable for full cover of the electricity demand by the combined system of PV and FC. Though it is expected that the smaller number of households below 12 indicates the larger self-sufficiency, it is necessary to consider the large electrolytic H2 storage system for the excess power generated by the PV system instead. In addition, it is assumed that one story consists of 4 households. Consequently, this design study decides that 12 households is the optimum for the proposed BIPV system with FC system.
The relationship between the households number and self-sufficiency rate of FC system per solar PV installation area has been shown in
radiation is smaller than the other cities. Therefore, the self-sufficiency rate for Ise is the smallest. Owase is also located in the south area in Mie prefecture and it is easy to rain, resulting that the self-sufficiency rate becomes smaller. In the future work, the energy network system consisting of several BIPV system assumed to be installed in several cities will be investigated in order to cover the electricity demand of each other through H2 transportation/infrastructure.
This study has proposed a combined PV and FC utilizing electrolytic H2 produced with surplus power of PV for Japanese buildings. The self-sufficiency rates of the combination system of PV and FC have been investigated using meteorological data of five cities in Mie prefecture of Japan. As a result, the following conclusions have been drawn:
1) The power production of PV system increases from the morning up to the noon and decreases from the noon up to the evening. The monthly power of PV system is higher in spring and summer, while it is lower in autumn and winter irrespective of cities.
2) The monthly power of FC system is higher in spring and summer, while it is lower in autumn and winter irrespective of cities. It follows the power generation characteristics of PV system.
3) The self-sufficiency rate of FC system is higher with decreasing households number, resulting that 12 households are suitable for full cover of electricity demand by the combined system of PV and FC.
4) The relationship between the households number and self-sufficiency rate per solar PV installation area can be expressed by the exponential curve well. We can find the city, which is more suitable for the proposed BIPV system using the appropriate coefficient of the exponential curve.
Nishimura, A., Kitagawa, S., Hirota, M. and Kolhe, M.L. (2017) Energy Assessment of Building Integrated Photovoltaics and Fuel Cell Systems: Design Study for Building(s) of Mie, Japan. Smart Grid and Renewable Energy, 8, 129- 144. https://doi.org/10.4236/sgre.2017.85009