442
Y. Shimada et al.
29.1 Introduction
In Thailand, where economic development continues, energy demand is expected to
increase in the future. The fuel used for power generation in Thailand is 64% for
natural gas and 18% for coal. In the future, the Thai government plans to reduce the
proportion of natural gas and increase the proportion of coal (Electricity Generating
Authority of Thailand Electricity Generating Authority of Thailand 2017). Therefore,
the deployment of high efficiency equipment is urgently required to reduce greenhouse gas emissions and mitigate air pollution in Thailand. Among the electricity
consumers, air conditioner accounts for a large portion of total electricity consumption, owing to the large demand for cooling. For instance, approximately 60% of electricity in commercial buildings are consumed for air conditioning (Chirarattananon
and Taweekun 2003). Therefore, the deployment of high efficiency air conditioning
system will play an important role for reducing greenhouse gas emissions such as
CO 2 , NO X and air pollutant emissions such as SO 2 .
A ground source heat pump (GSHP) has been known as the one of the high
efficiency air conditioning system in general. Although GSHP had been considered
as not appropriate for the tropics because of their high subsurface temperature, a
geological survey clarified the subsurface temperature in Chao Phraya Plain is lower
than the atmospheric temperature within the depth of 20–50 m. Therefore, GSHP
in this plain could have potential to achieve high efficiency, even in the tropics
(Yasukawa et al. 2009). Based on this survey, a pilot study of GSHP in Bangkok
was conducted to verify its potential in comparison to the conventional system, i.e.,
an air source heat pump (ASHP). As a result of the pilot study, GSHP could reduce
electricity consumption by 30% from that of ASHP (Chokchai et al. 2018).
The pilot study was conducted in a small room with a total floor area of 15 m
2 .
However, when considering the deployment of GSHP in the tropics, it is vital to
evaluate their performance in a large-scale facility, such as a super market.
Moreover, as GSHP in this plain requires construction work for embedding heatexchange pipes to the subsurface until the depth of 50 m, it is essential to evaluate
not only the environmental load during the operation stage but also during the entire
life-cycle stage.
Several studies on life-cycle assessment (LCA) of GSHP have been carried out
in the United Kingdom, China, and Japan. The LCA study in United Kingdom
was performed to clarify the environmental performance of GSHP over gas boilers
(Greening and Azapagic 2012). In the case of China, the LCA study was performed
based on the experimental data to clarify the changing in the environmental performance depending on the material of the ground heat exchanger (Ren et al. 2018). In
the case of Japan, the LCA study was carried out assuming introduction to a residential house in Sapporo city, northern part of Japan (Nagano et al. 2006). In each
case, detailed analysis was performed based on the actual data.
However, except in the case of Japan, few studies have been found where an LCA
has been performed by designing a ground heat exchanger that is optimal for the
building size, cooling load, and taking regional characteristics into consideration.
Y. Shimada et al.
29.1 Introduction
In Thailand, where economic development continues, energy demand is expected to
increase in the future. The fuel used for power generation in Thailand is 64% for
natural gas and 18% for coal. In the future, the Thai government plans to reduce the
proportion of natural gas and increase the proportion of coal (Electricity Generating
Authority of Thailand Electricity Generating Authority of Thailand 2017). Therefore,
the deployment of high efficiency equipment is urgently required to reduce greenhouse gas emissions and mitigate air pollution in Thailand. Among the electricity
consumers, air conditioner accounts for a large portion of total electricity consumption, owing to the large demand for cooling. For instance, approximately 60% of electricity in commercial buildings are consumed for air conditioning (Chirarattananon
and Taweekun 2003). Therefore, the deployment of high efficiency air conditioning
system will play an important role for reducing greenhouse gas emissions such as
CO 2 , NO X and air pollutant emissions such as SO 2 .
A ground source heat pump (GSHP) has been known as the one of the high
efficiency air conditioning system in general. Although GSHP had been considered
as not appropriate for the tropics because of their high subsurface temperature, a
geological survey clarified the subsurface temperature in Chao Phraya Plain is lower
than the atmospheric temperature within the depth of 20–50 m. Therefore, GSHP
in this plain could have potential to achieve high efficiency, even in the tropics
(Yasukawa et al. 2009). Based on this survey, a pilot study of GSHP in Bangkok
was conducted to verify its potential in comparison to the conventional system, i.e.,
an air source heat pump (ASHP). As a result of the pilot study, GSHP could reduce
electricity consumption by 30% from that of ASHP (Chokchai et al. 2018).
The pilot study was conducted in a small room with a total floor area of 15 m
2 .
However, when considering the deployment of GSHP in the tropics, it is vital to
evaluate their performance in a large-scale facility, such as a super market.
Moreover, as GSHP in this plain requires construction work for embedding heatexchange pipes to the subsurface until the depth of 50 m, it is essential to evaluate
not only the environmental load during the operation stage but also during the entire
life-cycle stage.
Several studies on life-cycle assessment (LCA) of GSHP have been carried out
in the United Kingdom, China, and Japan. The LCA study in United Kingdom
was performed to clarify the environmental performance of GSHP over gas boilers
(Greening and Azapagic 2012). In the case of China, the LCA study was performed
based on the experimental data to clarify the changing in the environmental performance depending on the material of the ground heat exchanger (Ren et al. 2018). In
the case of Japan, the LCA study was carried out assuming introduction to a residential house in Sapporo city, northern part of Japan (Nagano et al. 2006). In each
case, detailed analysis was performed based on the actual data.
However, except in the case of Japan, few studies have been found where an LCA
has been performed by designing a ground heat exchanger that is optimal for the
building size, cooling load, and taking regional characteristics into consideration.