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Heating - Solar air heater - Industrial / Korea, Rep. of (South)
Case study assignment
A government energy research agency in South Korea wishes to conduct research on solar air heating (SAH) technologies and to develop a SAH demonstration project. The agency has identified a local industrial building in need of a ventilation system as a likely candidate to demonstrate solar air heating in South Korea. You have been asked to assess the potential of this site and the financial viability of the project.
Site information
The building is located in Taejon, South Korea. The nearest meteorological station is in Seoul. The building is in an urban area, and has a long unshaded wall facing nearly due south. The wall is 25 m long by 3 m high and has 8 square windows, each 1 m². The total floor area of the building is 625 m² and it is used for light manufacturing. The building is uninsulated and the south wall is constructed of 12-inch insulated concrete block with an RSI value of 1.5.
Occupancy is approximately 30 people who are present between 8:00 a.m. and 5:00 p.m. Monday through Friday and from 9:00 a.m. to 12:00 p.m. on Saturday. The current building does not have any mechanical ventilation and is heated using conventional heating oil. The client is interested in minimizing the use of the additional fuel that will be needed to heat the ventilation air. The heating season generally lasts from mid-September to mid-May. There are no real destratification opportunities for this project.
Financial information
The solar air heating system will be paid for without any debt financing. The applicable discount rate is 7%, inflation is 2% and fuel costs are expected to increase at 3%. The SAH cladding is expected to last at least 30 years. It is estimated that the cladding can be supplied in Korea at a cost of about KRW85,000/m² (shipping included). Heating oil is currently priced at KRW600/L.
Prepare a RETScreen study, documenting any assumptions that you are required to make, and report on the significant conclusions from this analysis.
Solution
The worked-out solution is the data file selected from within the RETScreen Project Database. The user automatically downloads the Project Database file while downloading the RETScreen software.
Teacher's notes
Real project
Results
The Korean Institute of Energy Research (KIER) has identified solar air heating (SAH) as a promising technology to help reduce greenhouse gas emissions in South Korea. As part of a demonstration project, KIER has installed a SAH system at a light-manufacturing building known as "K-Site" in the city of Taejon. The previously unventilated building required a ventilation system and the SAH system was installed to minimize additional heating fuel consumption.
Because the installation is a demonstration project, financial viability was not seen as a primary objective.
System description
The SAH collector spans nearly the entire useable space on the south wall. Approximately 60 cm at the bottom of the wall are not covered by the collector to allow for snow build-up in the winter. Eight windows, each 1 m², reduce the available wall space even further. Vertical support columns protrude by 15 cm from the wall and prevent the installation of one continuous collector with a single inlet for heated ventilation air. The resulting collector is segmented into six sections by the support columns and has a total area of 53 m².
KIER was also interested in utilizing photovoltaic (PV) electricity to power the ventilation fans for this project. Six fans were installed, one for each collector segment, and are powered directly by the PV panels. Each fan provides 300 cubic feet per minute (CFM) of airflow at full sun. The building's operating schedule coincides well enough with daylight hours to ensure adequate ventilation. On cloudy days, only minimal ventilation is provided.
Lessons learned
South Korea has recently started a number of new initiatives, including the promotion of renewable energy sources, to reduce its greenhouse gas emissions. The Korean Institute of Energy Research is a government agency, with ties to the university system, charged with conducting research in the production and use of energy. This mandate includes investigating renewable energy technologies suitable for use in South Korea.
Particularly in North America, SAH technology has proven itself as an excellent means of reducing the conventional energy use (as well as fuel costs and GHG emissions) associated with providing ventilation and process air heating. KIER has set out to investigate and demonstrate SAH systems for South Korea. KIER's demonstration project in Taejon is one of the first SAH installations in the country.
Photo
Industrial building - Solar air heater, Taejon, Korea, Rep. of (South)
References
Case study assignment
A government energy research agency in South Korea wishes to conduct research on solar air heating (SAH) technologies and to develop a SAH demonstration project. The agency has identified a local industrial building in need of a ventilation system as a likely candidate to demonstrate solar air heating in South Korea. You have been asked to assess the potential of this site and the financial viability of the project.
Site information
The building is located in Taejon, South Korea. The nearest meteorological station is in Seoul. The building is in an urban area, and has a long unshaded wall facing nearly due south. The wall is 25 m long by 3 m high and has 8 square windows, each 1 m². The total floor area of the building is 625 m² and it is used for light manufacturing. The building is uninsulated and the south wall is constructed of 12-inch insulated concrete block with an RSI value of 1.5.
Occupancy is approximately 30 people who are present between 8:00 a.m. and 5:00 p.m. Monday through Friday and from 9:00 a.m. to 12:00 p.m. on Saturday. The current building does not have any mechanical ventilation and is heated using conventional heating oil. The client is interested in minimizing the use of the additional fuel that will be needed to heat the ventilation air. The heating season generally lasts from mid-September to mid-May. There are no real destratification opportunities for this project.
Financial information
The solar air heating system will be paid for without any debt financing. The applicable discount rate is 7%, inflation is 2% and fuel costs are expected to increase at 3%. The SAH cladding is expected to last at least 30 years. It is estimated that the cladding can be supplied in Korea at a cost of about KRW85,000/m² (shipping included). Heating oil is currently priced at KRW600/L.
Prepare a RETScreen study, documenting any assumptions that you are required to make, and report on the significant conclusions from this analysis.
Solution
The worked-out solution is the data file selected from within the RETScreen Project Database. The user automatically downloads the Project Database file while downloading the RETScreen software.
Teacher's notes
- The design objective is to minimize conventional fuel use by maximizing the renewable energy contribution from the Solar Air Heating (SAH) system. The building type is therefore set to "Industrial" to allow the user to set the minimum delivered air temperature to the lowest acceptable value of 13 °C (the ASHRAE recommended minimum temperature to introduce air into a space). The lower this value is the more usable solar energy can be delivered by the SAH system. In addition, on cold days when the solar collector alone cannot deliver air at 13 °C, the industrial SAH system reduces the airflow through the collector and further raises the incoming air temperature by mixing in some warm recirculated air from inside the building.
- Building temperature stratification is set to zero because the low building height prevents any significant stratification from occurring.
- For this building, the collector is designed to deliver twice the ventilation rate of about 1,000 m³/h, which is the default suggested by the User Manual (30 occupants x 36 m³/h/occupant = 1,080 m³/h).
- The SAH collector is sized to fit the available wall area. It is larger than recommended by RETScreen, but this serves to maximize the solar heating contribution and reduce fuel oil use.
- The velocity of the wind hitting the solar collector has a significant influence on the estimated energy delivered by the solar air heating system. Obstacles such as other buildings, trees and fences will typically attenuate, but in some cases even intensify, the wind speed hitting the solar collector. In this case, a 0.70 wind sheltering coefficient is assumed (this was done by multiplying each of the wind speed values by 0.70 in the climate data section of the Start worksheet).
- The cost for "Feasibility Study" is not included because the government agency is funding the SAH installation as a research project.
- Labour costs in South Korea are very similar to those in Canada. At the time of this analysis, the conversion rate between Canadian dollars and Korean Wons was KWR850 to CAD1.
- Fan and ducting costs, and fan power consumption, are estimated to be equal for both the base case (which involves the installation of a conventional ventilation system in a previously unventilated building) and the SAH case. The actual project's use of six separate fans and photovoltaic panels is not included in the analysis.
Real project
Results
The Korean Institute of Energy Research (KIER) has identified solar air heating (SAH) as a promising technology to help reduce greenhouse gas emissions in South Korea. As part of a demonstration project, KIER has installed a SAH system at a light-manufacturing building known as "K-Site" in the city of Taejon. The previously unventilated building required a ventilation system and the SAH system was installed to minimize additional heating fuel consumption.
Because the installation is a demonstration project, financial viability was not seen as a primary objective.
System description
The SAH collector spans nearly the entire useable space on the south wall. Approximately 60 cm at the bottom of the wall are not covered by the collector to allow for snow build-up in the winter. Eight windows, each 1 m², reduce the available wall space even further. Vertical support columns protrude by 15 cm from the wall and prevent the installation of one continuous collector with a single inlet for heated ventilation air. The resulting collector is segmented into six sections by the support columns and has a total area of 53 m².
KIER was also interested in utilizing photovoltaic (PV) electricity to power the ventilation fans for this project. Six fans were installed, one for each collector segment, and are powered directly by the PV panels. Each fan provides 300 cubic feet per minute (CFM) of airflow at full sun. The building's operating schedule coincides well enough with daylight hours to ensure adequate ventilation. On cloudy days, only minimal ventilation is provided.
Lessons learned
- The Taejon SAH installation, through trouble free operation, has helped demonstrate the value and reliability of SAH technology in the South Korean market.
- The high cost of heating oil and cold winters in Taejon indicate that SAH systems can be financially very attractive in a broad range of air heating applications in the region.
- In some cases, electricity produced by photovoltaic panels can be used to power the ventilation fans in a SAH system.
- SAH system designers should take into account local aesthetics and preferences when choosing the colour for SAH absorbers.
South Korea has recently started a number of new initiatives, including the promotion of renewable energy sources, to reduce its greenhouse gas emissions. The Korean Institute of Energy Research is a government agency, with ties to the university system, charged with conducting research in the production and use of energy. This mandate includes investigating renewable energy technologies suitable for use in South Korea.
Particularly in North America, SAH technology has proven itself as an excellent means of reducing the conventional energy use (as well as fuel costs and GHG emissions) associated with providing ventilation and process air heating. KIER has set out to investigate and demonstrate SAH systems for South Korea. KIER's demonstration project in Taejon is one of the first SAH installations in the country.
Photo
Industrial building - Solar air heater, Taejon, Korea, Rep. of (South)
References
- Dong-Un, Kang, "Personal communication," Forming Corporation, February 2002.
- Euy-Joon, Lee, "Personal communication," Korean Institute of Energy Research, February 2002.
- Kemp, Steve, "Personal communication," Enermodal Engineering Ltd., 2002.
- NRCan, CETC-Ottawa, Buildings Group, Enermodal Visit to KIER, report by Enermodal Engineering Ltd., 2001.
