Energy audit and air-conditioning system renovation analysis on office buildings using air-source heat pump in Shanghai

Abstract

In the past, the building energy consumption was surveyed without distinction of air-conditioning system types, which caused large dispersal of the energy consumption of the same building type. To study energy consumption of office buildings using air-source heat pump, six office buildings using air-source heat pump in Shanghai were investigated through energy audit and field test. The energy use intensity (EUI) per annum ranged from 102 to 139 kWh/m², with an average value of 126 kWh/m². The EUI range of office buildings using air-source heat pump is much smaller than the EUI of office buildings according to the literature. Based on field test of the air-conditioning (A/C) system, it was found that the present main problem of A/C system included insufficient refrigeration capacity of A/C system, low A/C system energy efficiency, and small cold water temperature difference. Countermeasures were brought forward to solve the problems, including ① retrofitting part of the present air-source heat pumps to water-cooled cold water air-conditioners, ② retrofitting present air-source heat pumps into new air-source heat pumps, and ④ pump variable frequency renovation. The A/C load is estimated by Bin method. According to the case study in this paper, the pay back period are about two years for the first measure, five to seven years for the second measure, and 0.65–2 years for the third measure.

Practical application: Generally, the energy consumption survey gives a wide range of data. To some extent, it is caused by the survey method which does not take the air-conditioning type into consideration. The work stresses on the energy consumption of office buildings using air-source heat pump. The result showed that the energy consumption was in a relatively small range, which will be more meaningful to industry. Energy saving measures concerning air-conditioning system is studied on the basis of the survey.

Keywords

Office building air-source heat pump energy audit energy saving renovation measure

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References

Jiang

. Analysis of national and local energy-efficiency design standards in the public building sector in China. Energy Sustain Dev 2011; 15: 443–450.

Yang

Lam

Tsang

. Energy performance of building envelopes in different climate zones in China. Appl Energy 2008; 85: 800–817.

Wang

. Building energy research in Hong Kong: a review. Renew Sustain Energy Rev 2009; 13: 1870–1883.

ASHRAE. 2007 ASHRAE handbook—HVAC applications. Atlanta: American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc., 2007.

Roulet

Blyussen PhM Ducarme

. Ventilation performance and energy consumption in European office buildings. Proc Healthy Build 1995, pp. 12991304–1304.

Balaras

Droutsa

Argiriou

. Assessment of energy and natural resources conservation in office buildings using TOBUS. Energy Build 2002; 34: 135–153.

Saidur

. Energy consumption, energy savings, and emission analysis in Malaysian office buildings. Energy Policy 2009; 37: 4104–4113.

Lam

Chan

ALS

. Building energy audits and site surveys. Build Res Inform 1995; 23: 270–278.

Lam

Wan

KKW

Yang

. Sensitivity analysis and energy conservation measures implications. Energy Convers Manage 2008; 49: 3170–3177.

10.

Papadopoulos

Theodosiou

Karatzas

. Feasibility of energy saving renovation measures in urban buildings: the impact of energy prices and the acceptable pay back time criterion. Energy Build 2002; 34: 455–466.

11.

JSM

. A study of energy performance and efficiency improvement procedures of Government Offices in Hong Kong Special Administrative Region. Energy Build 2008; 40: 1872–1875.

12.

Saidur

. A review on electrical motors energy use and energy savings. Renew Sustain Energy Rev 2010; 14: 877–898.

13.

Lonnberg

. Variable speed drives for energy savings in hospitals. World Pumps 2007; 494: 20–24.

14.

ANSI/ASHRAE/IES Standard 90.1-2010. Energy standard for buildings except for low-rise residential buildings. Atlanta: American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc., 2010.