DEVELOPING AN ENERGY EFFICIENCY ASSESSMENT TOOL FOR BUILDINGS ACCORDING TO USER BEHAVIOUR INDOORS Alción Alonso Frank Ernesto Kuchen Yesica Alamino Naranjo
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Regional Institute of Planning and Habitat, IRPHa. National University of San Juan, Argentina. Regional Institute of Planning and Habitat, IRPHa. National University of San Juan, Argentina. Regional Institute of Planning and Habitat, IRPHa. National University of San Juan, Argentina.
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[email protected] [email protected] [email protected]
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Fig. 1: Identification of user efficiency level. Example for UEL=4.
Research summary Efficient energy use is the most effective measure towards significantly reducing greenhouse gas emissions in order to improve the levels of environmental sustainability, and to guarantee the energy supply as a resource for social development. The behaviour of the energy user may seriously affect the running costs of the building, therefore, the user must be considered as an economic variable in the balance of running costs of the building. The purpose of this paper is to develop a tool for assessing how much influence the user has on energy efficiency, considering habits of energy use during the adaptation process of their comfort condition. To achieve this, three buildings with standard spaces are taken into account, users are surveyed and sensor measurements are performed at different periods in the year. Various actions are analyzed as regards the use of air conditioning devices, the opening of doors and windows, control of sunshade and curtains, and clothing modification, among others. The user habit actions are weighted into categories (good/bad) and they are divided into ranges to determine the degree of energy efficiency of the user. Results show that the user is responsible for a 33% decrease in the efficiency level that the building may reach. It is concluded that the use of the tool has a significant importance since it would not only allow obtaining relevant information for measuring rational use of energy, but also serve as an awareness and rationalization instrument for users indoors. Keywords: energy monitoring, user behaviour, RUE
1. Introduction In order to achieve the goal set at international level on Energy care, pursued from the 70s, because of the appearance of oil shortage, it is essential to introduce fundamental changes in the way of production and consumption of societies (Bugoni, 2004; Acosta & Cilento Sarli, 2007). The efficient use of energy is recognised as the most effective measure, in the short and medium term, in order to achieve a significant reduction of greenhouse gas emissions (Lutz, 2003), responsible for global warming (Doménech Quesada, 2007). Energy Efficiency (EE) is the use of minimum energy resources as possible, without affecting the user comfort (Poveda, 2007). In Argentina, the Executive Branch of the Government (Executive Order No. 140, 2007) declared the Rational Use of Energy (RUE) to be in the national interest and a priority. The National Programme for the Rational and Efficient Use of Energy in Buildings (PRONUREE), states the need to provide a tool enabling its realization. In order to do this, it implements labelling of Power Consumption Devices (PCD), with the objective of informing the consumer the EE of the equipments (see ENRE, 2014) and recently the EE Regulation in buildings through the Energy Saving and Efficiency in Public Buildings Programme (PAyEEEP). Public Policies are not enough to solve the described problems, given that although highly levels of EE depend upon the strategies applied to the building, the users decisively participate through their habits, which may reduce significantly the energy consumption (Toranzo et al, 2012). During the occupation stage, an efficient building may cease to be if users do not use it properly (LabEEE, 2009) and in the same way, conventional buildings may considerably improve its efficiency based on the conscious performance of users.
The hypothesis of the work is that users are responsible “to a large extent” for the unexpected energy consumption for buildings functioning. To maintain high levels of energy efficiency habit changes in people must be practised based on passive strategies, which do not involve energy expenditures. In the present work, a tool for assessing the extent to which users affect the energy efficiency of the building is developed. User habits in actions leading to reach their thermal comfort are analysed, within different periods in the year, among which stand out the frequency of the use of air conditioning devices, the opening of doors and windows, control of sunshades and curtains and clothing modification. Three actual buildings with standard work spaces are taken into account. The contributions intend to serve the scientific community and as an instrument of awareness, able to be introduced in user manuals and as a form of information about the consumer selfbehaviour in the energy invoice. 2. Objective and Methodology With the aim of developing an energy efficiency assessment tool, the user behaviour in work spaces is analysed, just at the moment that the user modifies the comfort condition, which according to the proposed hypothesis, is the environment where the user may affect the energy consumption of the building. In doing so, an integral survey is carried out in three actual buildings and a spot-monitoring according to (Kuchen, 2008), through surveys in summer, winter and a transitional period, in different work spaces randomly chosen considering floor stratification and building orientation. In total, 391 surveys were collected
3. Development
thermal amplitude in the country >14K (Kelvin) and prevailing wind from the south-east sector. The buildings were built between the ‘50s and the ‘70s, have characteristics of bioclimatic design and low or no maintenance. Table 1 shows these characteristics in detail.
3.1 Assesment tool The relation between energy demand and consumption values in three study cases of similar characteristics allows detecting the problem. Generally, energy consumption is higher than the planned demand. The tool has as a purpose to assess user habits that may affect the energy efficiency of the building. 3.1.1 Observed cases Three office buildings are taken (see Figures 2.1, 2.2, 2.3) located in San Juan City, Argentina, in the altitude of 630 meters above the sea level, Latitude 31,6° South and Longitude 68,5° West, in warm temperate dry climate, with annual mean outdoor temperature of 17,2°C and average relative humidity of 53% (IRAM 11603, 1996). The region of analysis is characterized by high solar radiation >1000W/m2, sun hours >3300hs/year, the highest annual and daily Table 1: Monitored Buildings
Title Orientation/Facade Offices Surface [%] Cold Air Conditioning
BUILDING 1 National University of San Juan - Central ECU North-South 45,9 HVAC +Split unit
Hot Air Conditioning
Steam Boiler
Owner
Glass surface [%] (N=north; S=south; E=east; W=west) Dull surface [cm] Sunshades 2 Demand [kWh/m a] 2 Consumption [kWh/m a] Occupancy factor Users Surveyed Gender (F/M) More than 6 Hours Work/Day [%] Factor [MET] Factor [clo] (Su-Wi)
N=30. S=60. E20cm Yes. Movable 167,8 171 2 3 [m /Person] 84 27/57
52
32
60
1,53 0,75– 1,21
1,54 0,78 – 1,21
1,31 0,82 – 1,33
187,2 146,6
thickness >40cm Yes. Fixed
Central HVAC
2
2,5 [m /Person]
167,8 131
STRATEGY 1 2 3 4 5 6 7
A heater (thermostat) A Split/Air Conditioner Opening of windows Opening of doors Sunshade/curtains control Clothing adaptation Others: ________________
always ° ° ° ° ° ° °
FREQUENCY rarely ° ° ° ° ° ° °
often ° ° ° ° ° ° °
never ° ° ° ° ° ° °
not possible ° ° ° ° ° ° °
Fig. 3: Question about the use habits of the user in the work space (see Kuchen, 2008).
Table 1 provides an overall framework of characteristics to the analysis population of the users surveyed. In common, the analyzed buildings allow being compared by having similarities in orientation of the main facade, high offices surface, existence of HVAC systems in all cases, small glass surface with east-west orientation, thermal mass and proper design of fixed and movable sunshades. In relation to users are characterized by common factors as there is no gender predominance, average activity level given by MET factor (Metabolic Equivalent of Task) and similar clothing insulation given by clo factor (Clothing) in summer and in winter. 3.1.2 Tool To build the tool, from the reference survey, the statement about the habits or strategies the user of office spaces develops facing different experiences of thermal discomfort depending on the season of the year is analysed. The question is: “What measure do you use to control temperature at this time of the year? How often do you use it?”, and the user values using a 5 points scale (as LabEEE, 2009), regarding the options availability and frequency, as shown in Figure 3. From the question, the strategies show the actions available to the user. It is supposed
that frequent use of some strategies may influence to a greater or lesser extent the energy consumption of the building. Because of that, the 5 points scale is rated regarding the frequency of use of each strategy, with letters from “A” to “E”, corresponding the meanings “A” (very good), “B” (good), “C” (fair), “D” (poor) and “E” (very poor) and a score is given to every numerical equivalent of the 5 points scale according to (LabEEE, 2009). Table 2, describes score ranges regarding availability and frequency. Thus, it comes to interpret that some strategies frequently used, may correspond to an active user, more adapted to local climate and less dependent to air conditioning system to reach personal thermal comfort. Table 2: Scale of frequency and availability, of 5 points with rating and numerical equivalents RATING Score Numerical Equivalent
A
B
C
D
E
≥ 4,5 to 5
≥ 3,5 to
