Elsevier

Renewable and Sustainable Energy Reviews

Volume 13, Issues 6–7, August–September 2009, Pages 1560-1568
Renewable and Sustainable Energy Reviews

Current status of ground source heat pumps in Korea

https://doi.org/10.1016/j.rser.2008.10.005Get rights and content

Abstract

In Korea, ground source heat pumps (GSHP) have been gaining popularity for space heating and cooling. Because there are few sources of high-temperature geothermal energy in the country, public baths (25–40 °C) and geothermal heat pumps (∼15 °C) using low-temperature groundwater or ground are the most dominant direct geothermal uses. The Promotion Law of the New and Renewable Energy Development, Use and Dissemination, enacted in 2004, imposed an obligatory installation of space heating and cooling systems using new and renewable energy sources including geothermal energy for newly constructed public buildings (more than 5% of total construction cost). Between 2004 and 2007, ground source heat pump systems occupied about 60% of the total public installation of new and renewable energy equipment. Starting with 35.2 kW of two facilities in 2000, systems with the capacity of over 127.1 MWt have been installed in 551 buildings (facilities) as of August 2008. The vertical closed heat pump system (closed loop) and the groundwater heat pump system (standing column well type; SCW) occupied 65.1% and 29.3%, respectively, among the total GSHP systems installed. The depth of the vertical loops ranged between 65 and 250 m (average 159 m) and the well depth of the SCW system ranged between 150 and 600 m (average 391 m). The number of geothermal energy companies, installing the GSHP systems, that are officially registered in the relevant authority increased from 5 in 2000 to 397 in July 2008. This paper presents details of the current status of ground source heat pumps in Korea.

Introduction

The Republic of Korea (ROK) is one of the top 10 largest oil-consuming countries in the world [1]. Furthermore, most of the domestic energy consumed (over 85%) in the country is derived from imports [2]. To keep pace with a world wide struggle to reduce CO2 emissions and to cope with a rapid increase in oil prices, the Korean government has promoted the use of new and renewable energy (NRE hereafter) sources for various purposes, including residential heating and cooling. The Promotional Law of New and Renewable Energy Development, Use and Dissemination (revision of the 1987 Promotional Law of Alternative Energy Development) was enacted in 2004. The Law (article 12) and it is Enforcement Decree (article 15) enforced the obligatory installation of NRE systems for newly constructed and reconstructed public buildings and facilities. More than 5% of the total building constriction cost should be allocated for these systems.

Compared with many other countries such as Switzerland, Sweden, Canada, USA, and Iceland, Korea's use of NRE energy is still low [3]. The share of NRE sources in Korea's overall energy mix was 2.1% in 2004 [2]. The Korean government aims to raise this level to 5% in 2011 and 11% in 2030. To promote the use of NRE systems in public, commercial and residential buildings, the government subsidizes 30–80% of the total installation cost. Research and Development (R&D) funding for energy is relatively low (only 1.6% of the overall R&D budget), but the largest increase of funding has been found in the area of the new and renewable energy technologies, which has grown nearly fivefold during 2002–2006 [2].

In the meantime, following the enforcement of the obligatory installation of the NRE systems for public buildings and facilities in 2004, ground source heat pump systems are the first option for the public community. Over 60% of newly constructed public buildings during 2004–2007 adopted GSHP systems for space heating and cooling [4]. Because there are few sources of high-temperature geothermal energy in the country [5], utilization of ubiquitous shallow geothermal resources in de-centralized GSHP systems is an obvious option for space heating and cooling [6]. Until recently, small buildings have been the main targets for GSHP systems, but most recently the systems are being installed in very large residential and commercial buildings. Details of the GSHP systems in Korea are presented in this paper.

Section snippets

Climate and general geology

The Republic of Korea is located in the southern part of the Korean peninsular and covers 45% (99,601 km2) of the total peninsular area (Fig. 1). Korea is surrounded by the South, East and Yellow Seas, including 3200 small and large islands. The climate ranges between continental and oceanic climates and it features four distinct seasons [7]. The hottest season is in August (average 23–27 °C) and the coldest is in January (average −6 to 7 °C). The annual mean air temperature ranges between 7 and 15

Direct use of geothermal energy

Before 2000, bathing and swimming were unique forms of the direct use of geothermal energy in Korea [5]. There are a significant number of hot springs (233 geothermal wells and 452 hot spring facilities), especially in areas of granite (formed in Jurassic and Cretaceous periods), some of which can be traced to more than 1000 yr ago [5], [9]. The hot springs (water temperatures of 25–75 °C) are mainly distributed in the provinces of CN, CB and GN (see locations in Fig. 1b) [10], which coincide

Installation of GSHPs

Since 2004, ground source heat pumps have been seriously considered as one of the alternative heating and cooling systems. Starting with only 2 buildings in 2000, GSHP systems have been installed for 551 buildings and facilities for space heating and cooling as of August 2008 (among them, installation years of 99 cases are unknown). Initially, while GSHPs were mostly installed in public buildings, they were not installed in private (residential houses) or commercial buildings. With the increase

Regulations on GSHPs

Laws and regulations directly related to GSHPs include the “Promotion Law of New and Renewable Energy Development, Use and Dissemination (#8899)” and the “Groundwater Act (#9058)”. The Promotion Law designates the geothermal energy as one of the new and renewable energies (article 2(1)) and imposes the obligatory installation of new and renewable energy equipment for newly constructed governmental and public buildings and facilities (article 12(2)). The Presidential Decree (article 15(1)) sets

Conclusion

In this paper, the current status of GSHP systems in Korea was presented. In Korea, installations of GSHP systems are rapidly increasing in both private and public sectors. The GSHP systems are extremely energy efficient, clean and environmentally friendly. Recently, the Korean government announced that the share of renewable energy among the total energy use would be elevated to 11% in 2030 from 2.4% at present. In particular, dissemination of geothermal energy is scheduled to increase by 51

Acknowledgements

This work is financially supported by the Korean Ministry of Environment (Department of Soil and Groundwater). The author is grateful to Jin-Gu Yun, Su-Hyun Song, Jae-Woong Kim, Hyun-Mi Choi and Kwon-Young Moon at Kangwon National University for their collection of GSHP data in Korea.

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