Energy Performance of a Galician Hostel

Transcription

1 Chapter 1 - Nearly Zero Energy Buildings Energy Performance of a Galician Hostel Ruth Dominguez Sanchez Polytechnic University of Madrid, Built Environment, Madrid, Spain ruth.dominguez.sanchez@upm.es César Bedoya Frutos Polytechnic University of Madrid, Built Environment, Madrid, Spain cesar.bedoya@upm.es ABSTRACT: The research poses a simple question, How are the CO2 emissions in a Saint James way hostel? Is there any simple way to improve it? In order to answer this question a study of energy consumption levels and CO2 emissions in two Galician hostels of Saint James Way has been carried out through monthly billing consumption. Some factors that influence this energy use such as variety of users, collective rooms and the need of ventilation are reviewed. The worst performing one, Ribadiso de Abaixo was then monitored, deeply analyzed and some methods to reduce its consumption were proposed. 1 INTRODUCTION 1.1 Context The main pilgrimage route of Europe is Saint James Way, world heritage route towards the Cathedral of Santiago de Compostela (Spain). Among the several options the main way goes through France and Spain (Fig. 1). Tradition says that the remains of the apostle Saint James are buried there and it is still possible to follow these medieval routes up to his tomb. But not only religion can be the reason to get involved into this kind of adventure. The way goes through some of the most beautiful, historic and interesting countryside areas, before arriving in the distinctive Celtic region of Galicia, bordering the Atlantic. Figure 1.Saint Jacques way routes Figure 2.Example of abandoned house Hostels provided to the pilgrims to spend the night may be private or public. Most of the public ones are carried out through the refurbishment of constructions along the way that are unused or in bad conditions (Fig. 2). This is the case of the two hostels chosen to study within the Galician context: 43

2 Portugal SB13 - Contribution of Sustainable Building to Meet EU Targets - Casa de la Torre in Redondela (urban context). - Ribadiso hostel in Arzúa (middle of the countryside). Due to the lack of studies about energy consumption in hostels, both of them were analyzed through billing consumption in order to assess their CO 2 emissions. The one in Ribadiso de Abaixo was also monitored for one week to understand deeper its performance and think of possible ways of improvement. 1.2 Hostel Characteristics The number of registered pilgrims last year was and this number increases surprisingly fast, around 23% a year. During the peak periods, people can even spend the night in the floor of any sport facilities or other public buildings supplied by the councils due to the lack of accommodation. Therefore, there is a need of more hostels due to this situation. One of the most common strategies is to use the historical buildings nearby the way creating new spaces of opportunity. Refurbishments bring changes in technical parameters such as ventilation rates, occupancy levels, internal gains, thermal response and the subsequent change in energy consumption levels. The main challenge is to adapt the preexisting building to the new needs in order to optimize the performance. Hostels can be defined as a typology half-way between housing and hotel. But there is also a need of extra space, common areas, acoustic control and effective ventilation systems in order to improve the quality of the air. The main differences between the pilgrimage hostels and other accommodation types are: -Collective rooms: One of the main characteristics of this kind of spaces is that there are communal rooms with a huge range of sizes. These tend to be collective and mix used with all the rest of the spaces in the building (kitchen, dining room and bathrooms) to be shared. -Variety of users: The normal age range is between years old, but people from every age and condition can do it. Some data collected in Saint Jean du Pied du Port, South France, revealed that 51% use to be men and 49% women. This is translated into different comfort zones and personal conditions combined into the same space. -Need of ventilation: Normally 88% does it walking while the 12% left by bike. After several hours walking of physical activity the transpiration of the human body achieves high rates and therefore the need for ventilation and fresh air in these areas is important. On this matter, the reduced window to floor ratio that normally has vernacular architecture can become a problem. On the other hand low daylight levels become a secondary issue because pilgrims use these areas mainly to rest during the evening and night periods. Thus, the requirements of the new use, the inherent properties of the building and the technical options in the refurbishment have to be considered as a whole. 2 GALICIAN HOSTELS ANALYSIS 2.1 Climate and Location Galicia is a region located in the North-west of Spain. It has an Atlantic climate with mild temperatures throughout the year. The average range of temperatures is between 8ºC in winter and 20ºC in summer. With well over 1,000 mm a year this is considered the rainiest region of Spain. The two sites where the hostels are going to be studied are Ribadiso de Abaixo and Redondela (Fig. 3). The first one is part of the French Way (main route) and it is placed in the north of Galicia. The second one, Redondela, is part of the Portuguese Way and it has less affluence of pilgrims than the one in Ribadiso de Abaixo. Although both climates follow the same trend, the dry bulb temperature in Redondela is normally around two degrees higher than in Ribadiso (Fig. 4). 44

3 Chapter 1 - Nearly Zero Energy Buildings Figure 3.Location map Figure 4.External temperatures in Redondela and Ribadiso, Spain. 2.2 Electricity Consumption Monthly electricity consumption in each one of the hostels is shown in Figures 5 and 6. It shows an expectable sensitivity according to the seasons and the occupancy levels. Pilgrim s hostels are opened 365 a year. Both hostels have a maximum capacity of 62 occupants. Lighting and heating were unfortunately not metered separately. The heated area in Redondela s hostel is m². In Ribadiso the heated area is m². Heaters in both hostels are electric and used during night time, when the electricity is cheaper. Hostels are working normally from September to March, with slight deviations depending on the weather. They perform as expected with the highest level of consumption during the lowest temperatures. Some months experience unexpected fluctuations (e.g. November) due to the unpredictable number of pilgrims you may have each day. Figure 5.Sample of monthly energy consumption Figure 6.Sample of monthly energy consumption and external temperature of a hostel in Redondela, and external temperature of a hostel in Ribadiso, Spain ( ). Spain ( ). 2.3 CO 2 Emissions CO 2 emissions in accommodation receive less attention than other sectors although it accounts for the 25% of the total emissions for global tourism. There are no national or international benchmarks set up for hostels yet. Thus, they may be compared with the hotel CO 2 emissions. They have been calculated using a conversion factor provided by IDAE of 1kWh electricity = 0.44 kg CO 2 in the final consumption. After quantifying the CO 2 emission levels for both hostels (Fig. 7, 8) we can conclude that Ribadiso has the worst performance under a common typology and therefore it will be further analyzed. 45

4 Portugal SB13 - Contribution of Sustainable Building to Meet EU Targets Figure 7.Sample of monthly CO 2 emissions Figure 8.Sample of monthly CO 2 emissions due to electricity in a hostel in Redondela, due to electricity in a hostel en Ribadiso, Spain ( ). Spain ( ). 3 RIBADISO DE ABAIXO 3.1 Description Ribadiso de Abaixo hostel is located in the middle of the Galician countryside next to the Iso river. The original building was compound by two different volumes (583 m 2 gross area). After the refurbishment in 1992 a new one was placed in the north part of the plot, to place the restrooms (170 m²), and a wing with the rooms for handicap people (46 m 2 ). This last one connected with the original construction (Fig. 9). The building was during the XV siècle the hospital of the village for pilgrims and the only heating source at that moment was a chimney placed in the dining room. Nowadays, this was replaced by the use of the electrical heaters previously mentioned. Figure 9.Ground plan of Ribadiso de Abaixo hostel 3.2 Monitoring An average winter week was chosen to monitor the hostel (from 28/03/10 to 03/04/10). The weather station to extract the climate data is in Arzúa, 4 km away from the hostel. The occupancy levels during this week was high achieving the maximum during the 50% of the time (Fig. 10). The period of the year and the weather conditions are the two key factors that define the number of pilgrims. 46

5 Chapter 1 - Nearly Zero Energy Buildings Figure 10.Ocuppancy levels of Ribadiso hostel from 28/03/10 to 03/04/10 Figure 11. Monitoring of the dining and one of the bedrooms of the hostel during one week (from 28/03/10 to 03/04/10). One datalogger was placed in each of the areas to be analyzed: the dining room (Fig. 13) and the main bedroom. Both of them are double height spaces and are built with 750 mm granite walls. Results (Fig. 11) show that the temperatures were higher in the dining room even though the occupancy is lower than in the bedrooms. This might be due to the different proportion of heaters by m². In the dining we found four units for 38 m² while in the bedroom there are five for 71 m². It is necessary to make use of the adaptive opportunity in the bedrooms in order to achieve the comfort zone, while in the dining with external temperatures between 5 C and 10 C (Fig. 14) it is relatively easy. Figure 12.Monitoring of the main bedroom of the hostel (02/04/10) 47

6 Portugal SB13 - Contribution of Sustainable Building to Meet EU Targets The graph (Fig. 12) reflects clearly that the leaving time is at 8:00 am in the morning with a drop in the temperatures. Due to reduced number of windows and their small dimensions (window to floor ratio of 5%) the solar gains are practically null. Figure 13.Dining room Figure 14.Average temperatures in Ribadiso hostel According to these results the worst performing area is the main bedroom. Further analysis was undertaken through thermal simulations on this area, trying to reduce energy consumption levels and to achieve the comfort zone. 3.3 Analysis A thermal model was built up using TAS software and calibrated with data taken from the datalogger of the main bedroom. The input for the current situation is: -Wall: Granite 750 mm covered with wood boards. U-Value kwh/m 2 -Ground: kwh/m 2 (No insulation) -Roof: U-Value kwh/m 2 (40 mm of insulation) -Windows: Single Glazing (6mm) with a U-Value kwh/m 2 -Frames: Teak wood frames and internal blinds The schedules used for the simulation are: -Lighting schedule: 18:00-23:00 -Occupancy: 19:00-20:00 -Heating schedule: 24:00-19:00 The analysis is focused on heating consumption. Cooling is not required within this climate zone. Temperatures are not extremely high during the summer period and the river and all the thermal mass of the building contributes to cool down temperatures (Fig. 15). Figure 15.General view of the hostel next t the river. Figure 16.Annual consumption before and after the improvement of the main bedroom. As a baseline a first analysis was undertaken with granite walls, leaving only the stone in the whole height to see how the structure of the building can perform by itself. Due to the high U- Value of the granite compared with other vernacular materials (e.g. brick) the performance is poor. Heating consumption levels compared with the current situation are almost a 50% higher (Fig. 16). 48

7 Chapter 1 - Nearly Zero Energy Buildings To improve the current situation some changes are applied with minor architectural implications. The main target is to optimize the final performance without compromising the original building envelope and its layout. New conditions after the improvement are: -Wall: 750 mm of granite U-Value kwh/m 2, covered with wood boards till mid height. -Ground: kwh/m 2 (50 mm insulation) -Roof: U-Value kwh/m 2 (80 mm of insulation) -Windows: Low-E double glazing with a U-Value 1.81 kwh/m 2 Final annual energy consumption level after the improvement is kwh/m². This means achieving the comfort zone and a reduction of 50% compared with the current situation. To sum up, the strategies applied to the main bedroom are: -Insulating the floor -Insulating the wood boards for half height leaving the rest of the stone exposed to take advantage of the thermal mass -Extra insulation in the roof -Low-E double glazing with the preexisting teak wood frames The remaining heating load could be reduced by changing from an electrical heating system to gas. Gas boilers have the highest overall efficiency from primary energy to useful heat. They also have the lowest CO 2 emissions and the fastest response. Further improvements may be achieved by changing the current lamps, which are mainly incandescent into low consumption. They will contribute with savings in the range of 80% (Tab. 1). Table 1. Equivalence table between low consumption fluorescent and incandescent lamps. Low consume Incandescent Energy savings fluorescent (W) (%) (W) CONCLUSIONS AND FUTURE LINES OF INVESTIGATION Results show a great performance and energy impact of minor design changes. The benefits identified through the analysis are as follow: -Space heating bills can be reduced by up to 50 per cent -Direct impact on the CO 2 emissions, reducing them to more than a half. -Significant improvement in comfort levels -Value of the property is increased as a result of the upgrading Currently hostels are designed as common areas unifying people expectations in terms of comfort to only one target. A future line of investigation may be explored on how to achieve different levels of temperature within the same space. How to design the space so people can achieve different comfort zones within the same bedroom and optimize the consumption levels? REFERENCES Baker, N The Handbook of Sustainable Refurbishment. Riba Publications. Pages: 3-23, Baker, N Certification in the Hotel Sector; Does it actually reduce CO₂ emissions? Conference on Passive and Low Energy Architecture, Dublin. PLEA Deng, S. & Burnett, J A study of energy performance of hotel buildings in Hong Kong. Energy and buildings. Ramos Guallart. J., Panero Pardo, A., Camiruaga Osés,I. Tomé Ferreiro, P., Fernández Hermida, R. A arquitectura histórica y os criterios de rehabilitación. Pages: Smith, P Architecture in a climate change. A guide to sustainable design. Architectural press

8 Portugal SB13 - Contribution of Sustainable Building to Meet EU Targets Yannas, S Solar Energy and Housing Design. Volume 1. Principles, Objectives, Guidelines. Architectural Association Publications