Utilisation rationnelle de l énergie.

Transcription

1 Evaluation des charges résidentielles (électricité, eau chaude, chauffage) Utilisation rationnelle de l énergie. Pr. Jean-louis Lilien, Université de Liège. Source des informations : Annex 42 of the International Energy Agency Energy Conservation in Buildings and Community Systems Programme November 26 Rapports de projets menés par l unité TDEE de Montefiore. 1 Overview This report discusses the production of realistic standard electrical and domestic hot water consumption profiles suitable for use in the assessment and comparison of the economic, carbon and energy performance of residential cogeneration systems. The profiles specifically required were representative residential electrical consumption profiles (excluding Heating, Ventilation and Air-Conditioning (HVAC) loads) and Domestic Hot Water (DHW) consumption profiles. The profiles obtained needed to be suitable for assessing annual loads and would ideally be applicable in a number of countries. A further ambition was to provide energy profiles suitable for assessing the detailed operation of cogeneration systems, i.e. the profiles should be recorded in the order of second intervals. The main purpose of the profiles is to be a standard dataset which can then be used to allow comparisons between the energy performance of various residential cogeneration systems. Ideally the profiles should be as representative as possible of reality. 2 Methodology The methodology initially adopted for this work was to: Review existing studies and data collections, and ascertain which consumption profiles or profile generators were available. Obtain real data from these existing studies where feasible. Depending on the data availability, then analyse this against building and occupant characteristics. Produce standard datasets at as frequent a time interval as the data will allow, with supporting documentation for use. 3 Review of existing data collections and profile generators From a review of existing literature, as well as our own monitoring work, we know that domestic non- HVAC electrical energy consumption is primarily dictated by the following factors: Floor area of the dwelling Number of occupants Geographical location Occupancy patterns Seasonal and daily factors Ownership level of appliances

2 Fuel type for DHW, heating and cooking etc. Social status of occupants As the profiles are required for assessing the design of cogeneration systems for domestic properties, the effect of the number of occupants and the occupancy patterns is ignored, except for the effects on weekday and weekends generally. The rationale for this is that we cannot predict the number or working patterns of the likely occupants of any domestic property, therefore the cogeneration system must be designed to meet the likely range of consumptions for any particular dwelling. It was intended to retain social status as a determinant as the use of cogeneration systems can often be directed at certain social classes. In the UK this determinant makes little difference to the profiles, but we were not sure whether this would be the case in other countries. However, the small sizes of the datasets available outside the UK meant that in the end it was not possible to retain social status as an indicator. Ownership level of appliances is assumed to be linked to social status and is therefore also not considered directly. Floor area and geographical effects are self-explanatory, as are seasonal and diurnal effects. Due to the limited amount of data available, the geographical effects are considered only to differentiate between Europe and Canada. The final profiles produced therefore provide information on total consumption and consumption per unit floor area, by time of day and time of year. 3.1 Datasets The final monitored datasets used came from 8 countries, and were as shown in Table 1. Table 1 - Domestic Hot Water (DHW) and non-hvac Electricity Consumption Data Sets provided and used in this Subtask DHW Non-HVAC Electricity Country No. of Profiles (used in the analysis) Monitoring interval [min] No. of Profiles (used in the analysis) Monitoring interval [min] Canada 12 (1) 5 and 6 85 (57) 5, 15 * and 6 USA 4 (2) 1,5 and 6 9 (1) 1,5 and 6 Switzerland 1 (1) 6 NA NA Finland 6 (6) 6 6 (6) 6 Belgium 2 () 15 2 () 15 UK (69) 5 Germany Portugal NA NA 1 1 EU 3 (1) 6 NA NA 3.2 Obtaining the Standard non-hvac Electrical Consumption Profiles This approach yielded two sets of profiles: a European one and a Canadian one. * Only the 15 minute data was used in the profiles produced page 2

3 The European profile uses the UK social housing profiles obtained from the DTI study as its basis, and considers this data with that obtained from the other limited European data sets. The second electrical profile was produced from the Canadian dataset, which addresses the Canadian situation only. The derivation of both these profiles is discussed in more detail in sections Erreur! Source du renvoi introuvable. to Erreur! Source du renvoi introuvable Obtaining the Standard Domestic Hot Water (DHW) Consumption Profiles There were only a few Domestic Hot Water (DHW) consumption profiles available. 4 Methodology for Derivation of the European Domestic Electrical Energy Consumption Profiles The lack of any previous comparative study for International or European Domestic Electrical Energy Consumption Profiles meant that this work would be the first to try and establish such profiles. The relatively small number of energy profiles available means however that the profile derived from this work can only be suggested as a possible profile for Europe, as there is too small a sample to provide any statistical significance to the work. However, where the sample date can be compared to previously published national domestic electrical profiles, i.e. the UK, the profile shape is very similar, and it is only the magnitude that varies slightly. This therefore provides additional confidence that the data represents the domestic population. The methodology for producing the European Standard profiles is therefore to use the largest monitored dataset from the UK as the European profile, and then to show how individual countries case study dwellings domestic electrical consumption data compare to this profile. No adjustment is made to the UK profile, the comparisons shown are simply for information and to allow the end user of the information to come to their own judgement on the potential applicability or otherwise of the work in the countries concerned. The Electrical Energy Consumption Profiles produced for use for assessment of the performance of Cogeneration Systems in Residential Buildings in Europe should therefore be viewed in this light. They are probably best described as the first draft of a European Profile. Sections 5 to 7 therefore deal in order with the basis of the UK Electrical Domestic Profile dataset (and hence the proposed European Electrical Domestic Profile dataset); the comparison of this proposed dataset with other European Electrical Domestic Profiles; and finally a concise review of the exact contents of the data files provided for use as the European Domestic Electrical Consumption Profiles. 5 Social Housing Electrical Energy Consumption Profiles in the United Kingdom Social housing forms a significant part of the overall UK housing stock, and is of interest from an energy efficiency viewpoint as a number of social housing providers are closely examining many ways of reducing the energy bills for their tenants including cogeneration systems. This section of the report presents measured electrical energy consumption profiles for this sector in the UK, obtained over a period of 2 years. The measurements were all obtained at 5 minute intervals. Annual energy consumptions, daily and overall profiles were derived for the dwellings from the data. To create a link between the energy consumption profiles and socioeconomic factors a user survey was undertaken among the people living in the monitored dwellings. The survey included questions regarding the following aspects: the number of tenants living in the household, tenant s age, ownership of electrical appliances and the general times of use of appliances and occupancy in the household. The level of detail and confidence in the information available for this dataset has resulted in the decision to use this dataset as the basis for the European Energy Profiles. page 3

4 5.1 Introduction The housing stock of the United Kingdom consists of 25 Million households with an annual electricity energy consumption of 115TWh 1,2. Around 2 per cent of these dwellings can be considered as part of social housing and, using the UK average of 2.4 occupants per dwelling, it can be estimated that this sector of UK society is represented by 12 million people 3. These figures stress the large influence on overall UK domestic electrical energy consumption of this section of society. The behaviour patterns of people living in the social housing sector usually differ slightly from the average pattern; one indicator of this discrepancy is the rate of employment. National Statistics show that among people from the social housing sector 33% work, where the average of employment in the non-social housing sector (renting from private and owner-occupied) is 6% 1. There have been two reported end use monitoring campaigns in the UK where the electric energy consumption of individual dwellings was obtained. The Load Research Group of the Electricity Association undertook the monitoring of 12 homes and carried out a user survey where the household type, socioeconomic characteristics and the ownership level of appliances were recorded 4. Based on these data sets a load model for domestic electric energy consumption and load profiles has been developed by Stokes 5. Another monitoring campaign was undertaken by Newborough 6 where the energy demand data of 3 homes has been obtained. A user survey among a sample of over 1 adults has been conducted mainly in the south-east of England regarding the socio-economic aspects of energy use 7. The results of this investigation, such as ownership level, differences in consumption in different classes of society, and total energy consumption of certain appliances are usually used when modelling of domestic energy is carried out for the UK (for example Yao and Steemers 8 ). 5.2 Data collection This section deals exclusively with the electrical energy consumption of houses within the social sector. The data for this work is based on 4 monitoring projects with a total number of 9 homes. Monitoring took place between 22 and 25 in Newcastle (25 flats/england), Llanelli (18 town-houses and flats/wales), Nottingham (22 semi-detached houses/england) and Derry (25 semi-detached houses/northern Ireland). The monitoring duration of each project was 24 months and measurements were taken at 5 minute intervals. The data has been collected by EETS Ltd. 9 as part of the Domestic Field Trial Project 2 where the performance of PV systems in the domestic sector as well as the electric energy imported and exported from the dwellings was monitored. Although initially 9 dwellings were monitored, the number of useable records has been reduced by abnormally low or non-occupation of the dwellings to 69 sets. The floor area of the households varies between 52m 2 and 124m 2 with an average of 75m 2 and the average number of occupants per dwelling is 2.4 (ranging between 1 and 9 people), which is the same 1 National Statistics Online, Accessed February 26 2 Department of Trade and Industry, Accessed February 26 3 Domestic Energy Fact File 23, - Accessed February 26 4 Electric Association, Load Research Group, Accessed February 26 5 M. Stokes, A fine-grained load model to support low voltage network performance analysis, PhD Thesis, De Montfort University, Leicester, 25 6 M. Newborough, P. Augood, Demand-side management opportunities for the UK domestic sector, IEE proceedings generation transmission distribution,1999, I. Mansouri, M. Newborough, D. Probert, Energy Consumption in UK Households: Impact of Domestic Electrical Appliances, Applied Energy, R. Yao, K.A. Steemers, A method of formulating energy load profiles for domestic buildings in the UK, Energy and Buildings, 24 9 Energy Equipment Testing Service Ltd., Accessed February 26 page 4

5 as the UK average noted earlier. The dwellings use fossil fuel for space heating and DHW. The energy type for cookers and showers varies within the data sets. There are 19 households with electric cookers/showers, 2 households with gas cookers and electric showers and 3 households with fossil fuel powered cookers/showers. 5.3 Overall load profiles and total annual consumption To understand the range of electricity demand, the daily Winter (as represented by January) and Summer (as represented by July) profiles for weekday and weekend days, averaged over all the dwellings monitored and normalised for floor area, are presented in Figure 1 through to Figure 4 using deviation bars. The range encompassed by the bars is plus and minus one standard deviation from the mean value at that point. The base load of the demand in the four figures occurs overnight and is mainly from appliances in stand-by mode and appliances driven by a thermostat e.g. refrigerator. This base load ranges between 6 W/m 2. The figures show that there is not a significant difference in terms of base load between summer/winter and weekend/weekday. The main difference between the weekend and weekday profile is the period between 9:am and 4:pm, where the weekend profile shows a higher demand due to higher occupancy Power Demand/Floor Area [W/m2] : 2: 4: 6: 8: 1: 12: 14: 16: 18: 2: 22: Figure 1 - Normalised overall Winter Weekend profile page 5

6 2 18 Power Demand/Floor Area [W/m2] : 2: 4: 6: 8: 1: 12: 14: 16: 18: 2: 22: Figure 2 - Normalised overall Winter Weekday profile 2 18 Power Demand/Floor Area [W/m2] : 2: 4: 6: 8: 1: 12: 14: 16: 18: 2: 22: Figure 3 - Normalised overall Summer Weekend profile page 6

7 2 18 Power Demand/Floor Area [W/m2] : 2: 4: 6: 8: 1: 12: 14: 16: 18: 2: 22: Figure 4 - Normalised overall Summer Weekday profile Figure 5 compares the hourly profiles of the average power demand over all dwellings for the winter and summer season. The base load period starts at 3: and finishes at 6: with an average demand of 2W. The Winter Weekday profile shows a considerable morning peak caused by a larger lighting and possibly a space and DHW heating-related demand, e.g. distribution pumps. The Summer Weekend profile has a peak around 13: when food is usually prepared for lunch. The two winter power profiles peak at 75W and both represent a daily electrical energy consumption of ~1kWh. The energy consumption of the summer profiles amounts to ~7.8kWh per day with an evening peak around 45W. 8 Power Demand [W] winter weekday summer weekday winter weekend summer weekend 1 1: 4: 7: 1: 13: 16: 19: 22: Figure 5 - Comparison of overall Winter and Summer profiles page 7

8 Power Demand [W] winter weekday social sector summer weekday social sector winter weekday UK average summer weekday UK average 2 1 1: 4: 7: 1: 13: 16: 19: 22: Figure 6 - Comparison of UK average and social sector daily electric energy consumption profiles Figure 6 presents a comparison of the weekday profiles obtained for the social sector and the profiles recorded by the Electricity Association, here considered to represent the UK average. The figure shows that the period from midnight until 6am is very similar; including the base load. Evident is the missing morning peak in the summer weekday profile of the social housing data and the smoother shape of these records. Unfortunately nothing is known about the ownership level of appliances or the proportion of electrical space heating within the Electricity Association records but it is clear that the typical social sector profile shows a lower energy demand. The energy consumption of a UK average winter day is around 11.5 kwh, the figure for the social sector amounts to 1 kwh. Comparison of the annual electrical energy consumption per unit floor area supports this finding. The UK average amounts to ~55 kwh/m2/year (derived from the total domestic consumption, number of households and the average Floor area) whereas the social sector use ~43 kwh/m2/year [1,2,3]. The annual total electric energy consumption of the monitored social sector dwellings varies between ~8kWh and ~78kWh with an average of ~31kWh. 5.4 Analysis of Single Load Profiles As well as the overall profiles and the total consumption already presented, the base and peak load demands, along with the load factor, are further data that are useful in order to optimise the integration of microgeneration systems. Figure 7 shows the distribution of the monthly average base load demands for all the houses. This base load demand was considered to occur between midnight and 7:am for all the dwellings. The data is derived from the monthly averaged electrical load profile of each dwelling and it shows that the base load is generally between 5W and 2W independent of the time of year or week. The bins are labelled at the highest figure in each bin, e.g. the bin labelled 5W covers all values in the range to 5W. Figure 8 shows the Winter (January) weekday peak load distribution for the same set of data, averaged over 5 minutes. The majority of the dwellings have a recorded maximum electrical power demand between 5W and 2W. The monthly load factor (the ratio between average demand and the peak demand ) for January ranges between.15 and.52 (average.34). This figure provides an indication of the variation in load on the system, with a smaller figure indicating greater variation over the period. This figure shows that even where electricity is used for showering, the demand does not exceed 4kW on average in any 5 minute period. page 8

9 3 25 Number of Dwellings Base Load [W] Figure 7 - Distribution of monthly Base Load Winter Weekday data Number of Dwellings Peak Load [W] Figure 8 - Distribution of monthly Peak Load Winter Weekday data 5.5 User survey The user survey was undertaken among the occupants of the monitored dwellings, and 46 out of the 69 households have been interviewed face to face. The occupation and composition of the households, and their comparison with the UK average, is shown in Table 2 and Table 3. The results of the survey indicate that the majority of the interviewed people do not have a fixed pattern of activities during the day. As already noted, this sector has a relatively low percentage of employed people compared to the UK average. This means that, for example, the high power demand activity of clothes washing can be done in the course of the day rather than after work. This uncertain activity pattern is reflected in the size of the standard deviation during the daytime shown in Figure 1 page 9

10 through to Figure 4. The overall effect is that the predicted power demand levels can vary by up to 5% from the mean value over the course of a day. Table 2 - Occupation of surveyed households and the UK National Average 1 Number of persons in the household or more Proportion (National Statistics, 22) Proportion (present study) 29% 35% 16% 14% 5% 2% 33% 26% 15% 15% 7% 4% Table 3 - Composition of surveyed households Family composition Number of households 1 adult 15 1 adult + 1 child 5 1 adult + 2 children 4 1 adult + 3 or more children 4 2 adults 7 2 adults + 1 child 3 2 adults + 2 children 5 2 adults + 3 or more children 3 The ownership level of appliances obtained from the survey is compared with the results from Mansouri [7] in Table 4. The biggest discrepancy between the UK average and the social housing is the level of dishwashers. The possession of this appliance is likely to be even higher than shown here as the Mansouri data is from 1997.The people living in social housing spend more time watching TV (~1h/day) than the UK average (~5h/day) which is also reflected in the number of TV sets per household. 1 UK Office for National Statistics Online. Social_Trends_35_Ch2 edition Accessed 18 th January 27. page 1

11 Table 4 - Comparison of appliance ownership levels Appliances Average ownership level Social Sector Refrigeration Average ownership level UK Average TV 2.15 (all) 1.6 (Colour) DVD player/video 1.64 (Video and DVD).76 (Video only) Computer.33 - Hi-fi.74 - Electric kettle.91.9 Toaster.67 - Microwave Washing machine tumble dryer dishwasher.9.43 vacuum cleaner iron.8 1. The possession of vacuum cleaners is less than one because the interviewed dwellings had partly wooden floors. The results from the survey give a possible explanation for the overall lower consumption in the social sector. The ownership level of high demand appliances is, according to this user survey, lower than the average, taking into consideration that refrigeration and the dishwasher are the main consumers in the household. On the other hand, the possession of low demand appliances, such as TV and DVD player/video, is higher in the social sector than the average. 5.6 Conclusions This section of the report focuses on the domestic electrical energy consumption of the social housing sector in the United Kingdom. The data from a user survey and a monitoring campaign has been analysed and presented in this work. The monitored dwellings have been characterised regarding floor area, number of occupants and ownership level of appliances. Although the sample size of the investigation is relatively small, it still gives some useful information on the energy usage behaviour. The findings were compared with the available records for the UK average and the analysis indicates that there is a general lower consumption in the social sector. The difference can possibly be explained by the absence of high energy consumers such as dishwashers and a lower ownership level of refrigeration. A reasonable agreement was obtained from the comparison of the Electricity Association profiles 4 and the social sector profiles, and therefore as we do not have any further details of the EA dataset these Social Housing Profiles are presented as being the standard profiles for the UK domestic sector excluding HVAC loads. It should be noted that there is a small component of HVAC and DHW related electrical energy use in some of the data used in the UK profiles, principally for heating pumps and some DHW heating for showers. However, the duration of these loads are not deemed to be sufficiently large to be significant in terms of overall energy use. They are potentially significant in terms of peak electrical power demand, but none of the data available to the monitoring indicated demands greater than 4 kw over a 5 minute period, a peak load that would be within the expectations for a house without electrically page 11

12 heated DHW. The demands presented are believed to be suitable therefore for sizing domestic cogeneration systems. The format and data contained in the final electrical load profiles dataset for the UK will be discussed in section 7. The Domestic Hot Water (DHW) profiles will be dealt with as a separate dataset in section 8. 6 European Electrical Energy Consumption Profiles This section discusses the relationships observed between the detailed UK consumption profiles and the generally less extensively detailed energy consumption profiles obtained from other European states. Given the general lack of information available with each profile supplied, the work treats each profile as a Case Study rather than a representative sample for the country from which it was obtained. The methodology used to assess this data was to compare it with the general UK profiles previously established and discuss whether these Case Studies from each country showed similar magnitudes and profiles to the UK dataset. The overall findings from these comparisons were that the general UK profile appeared to be replicated in a number of the Case Studies in terms of increasing winter energy use compared to the summer, and also in terms of the timing of the peaks and troughs throughout the day. Whilst these observations are not sufficient on their own to provide confidence that the UK profiles are therefore applicable throughout Europe as well, it was decided that in the absence of any data indicating that they were not suitable for Europe, that they would serve this end. 6.1 Individual European Country Domestic Electrical Load Profiles In total we had domestic electrical load profiles or information supplied from 7 European Countries: UK, Finland, Italy, the Netherlands, Germany, Portugal and Belgium. For each country we have provided an overview of their average profile and the data this was obtained from, where known Finland The Finnish daily electrical consumption profile data was provided by the Technical Research Centre of Finland, VTT and has been obtained from 6 houses monitored at hourly intervals in Three of the houses were low energy exemplar houses and three were standard houses. All were connected to the local District Heating System. The number of occupants in the housing varied between 1 and 6 people, with an average of 3.7 occupants in the standard housing and 2.7 in the low energy housing. The floor areas are not known. Figure 9 shows that the Finnish Electrical consumption profiles exhibit similar characteristics to the UK profiles, in terms of general magnitude of consumption and the overall shape, though in this case the daily profile distribution refers to the whole year s data rather than the various parts of the year as shown in the UK profiles. The average annual consumption of the houses supplied was around 32 kwh in a range from 15 to 6 kwh. As there are only 6 houses in the sample, three of which are by definition not representative of the domestic Finnish population, then the best that can be said is that there is nothing in these profiles to suggest that the UK domestic profiles are not a reasonable estimate of the Finnish situation. page 12

13 VTT Electricity Consumption Daily Profiles - Standard and Low Energy Exemplar Finnish houses - District Heating kw Time of day Average - Standard Average - Low Energy Figure 9 Average Daily Electrical Consumption Profiles for Low Energy and Standard Finnish Housing Italy The Italian load profiles were provided by Università del Sannio, Benevento and Seconda Università degli Studi di Napoli at the April 26 Penn State University meeting, and have been derived from a dataset comparable to the UK dataset. The Italian domestic electrical non-hvac dataset has been obtained from a report of the Politecnico of Milano derived from on site measurements of the electric consumptions in the Italian residential sector for the SAVE EURECO and MICENE projects. This report considers data for: 11 flats located in 5 Italian regions analyzed for 3 years. The monitored electrical energy consumptions and electric power demand of the total household appliances and lighting systems. Electric energy consumptions and electric power demand of each flat and of the whole building. The measurement interval was 1 minutes, and this is apparently the only database of domestic electrical energy consumption available in Italy. The data provided did not include total annual consumption profiles or figures. Data from 1996 in another study 11 suggests an annual figure of around 2,7 kwh then, so it would be expected that this would have risen significantly since then, and a range of 3 35 kwh per annum in line with the other European countries would seem reasonable to expect. The occupancy characteristics of the monitored Italian sites are shown in Figure 1 and Figure 11. It can be seen that 77% of the sample consists of households of 3 or 4 people, and that the average household floor area is around 16 m Fawcett T, Lane K and Broadman B Carbon Futures for European households. Environmental Change Institute, Oxford University March 2. Country pictures supporting material Italy.. Accessed 7th January 27 page 13

14 5 persons 14% 2 persons 9% 4 persons 43% 3 persons 34% Figure 1 Household occupancy for the monitored Italian dwellings Figure 11 Floor areas of Italian Housing Sample. Due to the presence of electrically driven air-conditioning in many Italian Households the derived dimensionless PEAK electrical consumption graphs for a 7-day period shown in Figure 12 are only for Cool, Cold and Warm periods of the year, as the Hot periods of the year are distorted by the A/C HVAC demand. This data showed that the average PEAK load does not drop below 5% of the MAXIMUM PEAK load throughout the week in all 3 seasons. page 14

15 Pel/Pmax 1,9,8,7,6,5,4,3,2, Hours of week [-] WARM COOL COLD Figure 12 Dimensionless average electrical consumption profile for Italian Domestic Housing by day of week. Figure 13 presents the average daily profile in the cold season where it can be seen that the average baseload figure is less than 5W. Figure 13 also shows the normal morning and evening peaks seen in other country profiles - though it would be expected that there would be more of a lunchtime load due to cooking activities. 1 Elettric Power [kw],8,6,4, Hours [-] Figure 13 Italian Cold Season Daily Electrical Consumption Profile Figure 13 also shows that the magnitude of the Italian consumption profiles is very similar to those of the UK. page 15

16 P el /P max 1,9,8,7,6,5,4,3,2, Hours [-] U.S.A. U.K. Italy Figure 14 Comparison of Dimensionless non-hvac daily domestic electrical consumption profiles for the UK, USA and Italy With the caveat about the midday dip in the Italian profile in mind, Figure 14 appears to suggest that the use of the UK profile as the European profile would result in a reasonable match to the Italian domestic profiles. The Italians also refer to a US dataset in this figure which we do not have access to, but has been included here for information The Netherlands We did not have any daily electrical consumption profiles provided, but the following report 12 provided by the Energy Research Centre of the Netherlands, ECN gives an overview of the annual consumption in Dutch Households. The study is an annual survey of about 3 Dutch households. The most recent detailed report available describes the situation in 2, though the most recent annual average consumption dates from 23 (no details available). Table 5 shows the consumption trends over the years from 1995 to 23. The average total annual electricity consumption in the 3 Dutch households in 2 was 323 kwh. Based on the population size, the 95% interval limits are 3165 and 33 kwh. The most recent average reported consumption of 3,4 kwh per annum per household in 23 is similar to the monitored UK average social housing consumption of around 31 kwh per household, and very similar to the German 22 figure of 3,34 kwh per household. This similarity is as close as we can get to suggesting that the UK profiles are representative of the Dutch situation, though it suggests that the German and Dutch profiles might also be similar. Table 5 Average domestic annual electricity consumption for the Netherlands Year Household electricity consumption [kwh/year] The study from 2 offers some details on consumption as a function of household size, income, social status etc. See figures below. 12 Source: Basisonderzoek Elektriciteitsverbruik Kleinverbruikers 2 page 16

17 average Figure 15 - annual household electricity consumption in The Netherlands in 2 as a function of the number of people in the household. The study distinguishes between several social classes: A, B1, B2, C and D (from high to low). Two parameters define the social class: education and profession. The classes A to D cover the complete range found in society. page 17

18 average Figure 16 - annual household electricity consumption in The Netherlands in 2 as a function of social class (high to low, A to D). average Figure 17 - annual household electricity consumption in The Netherlands in 2 as a function of net household income per month (in NFl, divide by for euro) page 18

19 no boiler average Figure 18 - annual household electricity consumption in The Netherlands in 2 as a function of the number of electrical boilers for DHW The presence of an electrical boiler (for DHW) has a strong influence on the electricity consumption. Other Personal care Hobby Kitchen appliances Indoor climate Cooking Heating Audio/video/ communication Lighting Cooling Cleaning Figure 19 - annual household electricity consumption in kwh in The Netherlands in 2 as a function of the application The application categories in Figure 19 contain the following items: Cleaning: washing, drying, dishwasher, vacuum cleaner, ironing, etc. Cooling: refrigerator, freezer, etc. Heating: electrical boiler, central heating (fans, pumps etc), electrical heating, etc. Cooking: micro wave, furnace, oven etc. Indoor climate: ventilation, air-conditioning, etc. Other: doorbell, battery charger, sun shading, alarm, etc. page 19

20 The sum of the electricity consumption per application (3567 kwh) is a little higher than the average total electricity consumption. The study does not explain the difference. The study does not provide the average electricity consumption as a function of the type /size of the house. The average usable floor area in residences is about 11 m 2 in The Netherlands and the range is 59 to 172 m Germany The German profiles used for comparison in this report were supplied by the Research Institute for the Energy Economy (FfE), Munich, and are the representative residential load profiles used for Germany 13. An undated report from the Fraunhofer Institute 14 reports an average German Domestic Electricity consumption of 3,34 kwh per household per annum in 22 based on 2,235 households. It also reports 1,84 kwh per person per annum, suggesting an average household size of 1.8 people, which is less than the 2.4 people per household noted in the UK housing profiles. Representative load profiles normalised to the maximum consumption are given for the four seasons of the year and 3 different periods of each week Weekday, Saturday and Sunday. Figure 2 through to Figure 22 show these profiles. It can be seen that the difference between the morning and evening peaks is far less pronounced than with the UK profiles, as are the differences between the Winter and Summer profiles. Assuming that these profiles are still representative, then the use of the UK domestic profiles to represent the German situation is therefore not as secure as with some of the other countries compared, despite the overall average annual consumption of 3,34 kwh/household being very similar to the 3,1 kwh/household monitored in the UK social housing sector. Power Demand normalised with Maximum Winter Workday Winter Saturday Winter Sunday. : 2: 4: 6: 8: 1: 12: 14: 16: 18: 2: 22: : Figure 2 Winter representative domestic electrical consumption profile for Germany Time 13 Source: C. Fünfgeld, BTU Cottbus - Chair of Energy Economy, October Gruber, E and Schlomann B The current and future electricity demand of appliances in German Households. Accessed January 3rd, 27. page 2

21 Power Demand normalised with Maximum 1. Summer Workday.8 Summer Saturday Summer Sunday : 2: 4: 6: 8: 1: 12: 14: 16: 18: 2: 22: : Time Figure 21 Summer representative domestic electrical consumption profile for Germany Power Demand normalised with Maximum 1. Spring/Autumn Workday.8 Spring/Autumn Saturday Spring/Autumn Sunday : 2: 4: 6: 8: 1: 12: 14: 16: 18: 2: 22: : Time Figure 22 Spring/Autumn representative domestic electrical consumption profile for Germany 6.2 Overall summary of European Domestic Electrical Energy Consumption Data supplied The overall data sets supplied for use by the various European countries varied in their content and detail. In the author s opinion the general conclusion is that the datasets where the monitored data could be more explicitly referred to all tended to exhibit similar daily profiles during the weekdays and similar overall magnitudes of consumption. The larger differences in the datasets tended to appear where it was more difficult or impossible to refer back to the original source data. Where we were able to assess the annual consumptions of the profiles supplied against various whole country data sources we generally obtained good agreement that the average European dwelling in each country tended to consume between 3 and 35 kwh of electricity per annum, excluding space and DHW heating energy use. It is the opinion therefore that, in the absence of further substantial datasets, the Standard and Specific European Electrical Consumption Profiles presented here, which are the UK domestic profiles monitored by EETS Ltd and the Welsh School of Architecture, are likely to be a good first estimate of domestic electrical energy consumption profiles for many European countries. They are therefore a page 21

22 reasonable basis for assessing the potential performance of Cogeneration systems when meeting this load. 7 The European Domestic Electrical Energy Consumption Profile Data provided by IEA. This section describes exactly what is in European Domestic Electrical Energy Consumption Profile datasets provided. The data for this work is based on 4 monitoring projects with a total number of 9 homes. Monitoring took place between 22 and 25 in Newcastle (25 flats/england), Llanelli (18 town-houses and flats/wales), Nottingham (22 semi-detached houses/england) and Derry (25 semi-detached houses/northern Ireland). The monitoring duration of each project was 24 months and measurements were taken at 5 minute intervals. The data has been collected by EETS Ltd. as part of the Domestic Field Trial Project where the performance of PV systems in the domestic sector as well as the electric energy imported and exported from the dwellings was monitored. Although initially 9 dwellings were monitored, the number of useable records has been reduced by abnormally low or non-occupation of the dwellings to 69 sets. The floor area of the households varies between 52m 2 and 124m 2 with an average of 75m 2 and the average number of occupants per dwelling is 2.4 (ranging between 1 and 9 people). The dwellings use fossil fuel for space heating. The energy type for cookers and showers varies within the data sets. There are 29 households with electric cookers/showers, 3 households with electric cookers and fossil fuel heated water for the showers and 1 households with fossil fuel powered cookers/showers. Table 6 European Domestic Electrical Energy Consumption Data Filenames Daily Consumption Period Month [kwh] Winter weekday January Winter weekend 9.84 January Shoulder season weekday April and October Shoulder season weekend April and October Summer weekday July Summer weekend July The six standard DAILY profiles provided and shown in Table 6 represent a monthly average of the 69 households at various times of the year, i.e. for each 5 minute timestep in the month indicated the average load at that time of day over all weekdays or weekend days across all 69 households is provided (ask IEA for CDrom details) The time resolution of each profile is 5 minutes and the unit is Watts (W). To obtain a full year s profile the user can aggregate the profiles together in blocks of 3 months, using the weekend and weekday profiles as appropriate, as follows: Winter: December, January and February Shoulder Season: March, April, May and September, October, November Summer: June, July, August Three dwellings are those considered to be most representative of low, medium and high electric energy consumption amongst the sample of buildings monitored (see Figure 23 through to Figure 25) as their consumptions for the year chosen are those which provide the most complete high, average and low consumptions identified in the overall dataset. The profiles presented are the average power consumption over a 5 minute time interval in two flats in Newcastle (England) and one town house in Llanelli (Wales). These profiles are presented as being the best current option to represent standard European domestic profiles based on the data available. The data presented are complete annual files every 5 minutes. As with most monitoring projects there is some missing data. Missing data points are replaced by data points assumed to have the same characteristic (e.g. a missing Monday has been replaced by another existing Monday). This replaced data is marked in the file by a yellow cell. The files have a time and a day tag (day tag: 1=Monday, 2=Tuesday..). The monitoring fractions for the dwellings (the amount of data collected as a percentage of the maximum possible in that period) are shown in Figure 26 and Figure 27. The annual monitoring page 22

23 fraction for the files low electric energy consumption and medium electric energy consumption amount to 9.3% and for the file high electric energy consumption to 97.%. The unit of the energy consumption data is Watts (W) and the data starts on the first of each month on each sheet. Table 6 provides more detail on each of the properties. These three specific profiles do not include any electrically heated DHW. Table 7 Dwelling characteristics File Name Actual low electric energy consumption actual medium electric energy consumption actual high electric energy consumption Annual Consumption [kwh] Location Year Size dwelling [m²] of Occupancy type 1155 Newcastle Single male 328 Newcastle Llanelli Mother and two children Mother and 5 children Town houses (Llanelli - Wales) Flats (Newcastle England) page 23

24 14 12 Electric energy consumption [kwh] jan feb mar apr may jun jul aug sep oct nov dec Month Figure 23 - Monthly electric energy consumption file low electric energy consumption 35 3 Electric energy consumption [kwh] jan feb mar apr may jun jul aug sep oct nov dec Month Figure 24 - Monthly electric energy consumption file medium electric energy consumption page 24

25 1 9 Electric energy Consumption [kwh] jan feb mar apr may jun jul aug sep oct nov dec Month Figure 25 - Monthly electric energy consumption file high electric energy consumption Monitoring fraction [%] jan feb mar apr may jun jul aug sep oct nov dec Month Figure 26 - Monthly monitoring fraction file low electric energy consumption and medium electric energy consumption page 25

26 1 9 8 Monitoring fraction [%] jan feb mar apr may jun jul aug sep oct nov dec Month Figure 27 - Monthly monitoring fraction file high electric energy consumption 8 Domestic Hot Water (DHW) Consumption Profiles As well as representative Domestic non-hvac Electrical Consumption Profiles, it requires representative Domestic Hot Water (DHW) profiles to enable the overall economic, carbon and energy performance of residential cogeneration systems to be assessed through modelling. It however was unable to source many DHW profiles, and did not have a sufficient number to start proposing its own representative consumption profiles. However, in this task there was already a DHW model available from IEA SHC Task 26 that might be considered for use, and which provided the ability to model the DHW loads at intervals as frequently as 1 minute. The approach taken in this section of the report was therefore as follows: To assess and compare the monitored DHW profiles available in terms of annual consumption, profile and magnitude by country. To assess and compare these profiles with available DHW models in order to provide confidence in the model(s) to be used. To obtain other DHW data available to increase confidence in the models used. 8.1 DHW consumptions and profiles by country Table 1 is reproduced below showing the numbers of DHW profile datasets provided by country. Table 1 - Domestic Hot Water (DHW) and non-hvac Electricity Consumption Data Sets provided and used in this Subtask page 26

27 DHW Non-HVAC Electricity Country No. of Profiles (used in the analysis) Monitoring interval [min] No. of Profiles (used in the analysis) Monitoring interval [min] Canada 12 (1) 5 and 6 85 (57) 5, 15 * and 6 USA 4 (2) 1,5 and 6 9 (1) 1,5 and 6 Switzerland 1 (1) 6 NA NA Finland 6 (6) 6 6 (6) 6 Belgium 2 () 15 2 () 15 UK (69) 5 Germany Portugal NA NA 1 1 EU 3 (1) 6 NA NA Table 8 shows the daily DHW consumptions for a few countries in terms of the consumption per dwelling per day and consumption per person per day. It can be seen that DHW consumption ranges between 1 and 3 l/day per household, and between 2 to 94 l/day per person. This table also contains information from a draft report by VHK 15 which reviews the EU standards for DHW water heaters by country. It appears that again there is a split between the Canadian and European data, with the Canadians consuming approximately twice as much DHW per day as the Europeans. If we just use published data for comparison then the USA also consumes as much water per day as the Canadians. * Only the 15 minute data was used in the profiles produced 15 Kemna R, van Elburg M, Li W, van Holsteijn R Preparatory Study on Eco-design of Water Heaters. Task 1 Report (DRAFT). Definition, Test Standards, Current Legislation and Measures. VHK, Delft, December 26 page 27

28 Table 8 Daily DHW consumptions per household and occupant by country Country Daily DHW Consumption per Household [l/day] Daily DHW Consumption per Occupant [l/occupant*day] Source Canada 236 (33) (94) NREL Report USA 25 (22) 243 (at a 42.8 C rise) Switzerland NA (55 at a 5 C rise) (range from 24 to 74) (4) NREL Report USA water heater standard RAVEL (CH) (2 Buildings) Finland (135) (43) VVT (6 Houses) UK 117 (12) 116 (at a 45 C rise for a 1 m 2 dwelling) 39 (2) Yao, 24 UK water heater standard Germany NA (64) FFE France 1.74 per m 2 (at a 3 C rise) NA France water heater standard Spain NA 3 (at 6 C) Spain water heater standard Portugal 1 (at a 45 C rise) (apartments) 4 Portugal water heater standard The figures in brackets are derived from the data provided as shown in Table 1, other figures are derived from the published literature in this area. The table indicates that for an average 45 C rise in DHW temperature, European countries would generally consume around 1 to 12 litres/day for a dwelling with a 1 m 2 floor area. Reported Canadian and USA consumption is around twice this at about 2 to 25 litres/day, but the dwelling areas are not known. The following profiles represent the data provided by various countries. The data generally has very little information with it other than that already shown in Table 1, i.e we have little or not information on occupancy numbers, how the data was obtained, date of data collection, etc. This data has also come in various forms so please note the units on the Y-axis for each graph before attempting comparisons. page 28

29 UK (EPA) Annual Average Hourly Data DHW Consumption [l] :3 2:3 4:3 6:3 8:3 1:3 12:3 14:3 16:3 18:3 2:3 22:3 Figure 28 Average Daily DHW Consumption for the UK in litres per hour. This profile was obtained from the Welsh School of Architecture s Energy Performance Assessment measurements in the 199 s, and perhaps does not accurately reflect the current magnitude of usage within the UK. It reveals that on average the major DHW demand in the UK occurs in 2 peaks during the day an early morning peak presumably coinciding with the morning shower or bath, and a smaller evening peak coinciding with the evening meal and possibly children s bath time it appears. Germany (FFE) Annual Average Hourly Data DHW Consumption/number of Occupants [l/occupant] : 3: 5: 7: 9: 11: 13: 15: 17: 19: 21: 23: Figure 29 - Average Daily DHW Profile for Germany. Profile is in terms of litres per occupant per hour. This profile was supplied by the Research Institute for the Energy Economy (FfE), Munich. It shows that peak demand occurs in the morning though slightly later than in most countries, with a lower evening peak. A four person household would on average have a peak demand of around 25 litres per hour at 8:. page 29

30 8.1.1 Comparison of the DHW profiles provided Figure 3 plots all the previous figures on a single graph by converting them all to a % of daily DHW consumption by hour. It also shows the average profile drawn from all the data given. This average profile clearly shows the morning and evening peaks seen in most of the data. Comparison of Annex 42 DHW Profiles Percentage of DHW Consumption [%] : 3: 5: 7: 9: 11: 13: 15: 17: 19: 21: UK Canada USA (Hath) Switzerland Finland Germany EU Tapping Cycle USA (Model) Average 23: Figure 3 Comparison of DHW Profiles supplied loads given as a percentage of daily consumption per hour. 9 Overall summary This report has shown how standard non-hvac domestic electrical consumption profiles and standard domestic hot water (DHW) consumption profiles have been produced for use in assessing the economic, carbon and energy performance of cogeneration systems in residential properties. Reference to look at (for Canada) : bles/index.cfm?fuseaction=selector.showtree page 3

31 Field measurement of load profiles and energy consumptions in 2 residential houses in Belgium PROJET GREEN FAMILY (responsable : Université de Liège, Institut Montefiore, Pr J.L. Lilien, projet terminé en 26) cadre : IEA Annex 42 FC+COGEN-SIM The Simulation of Building-Integrated Fuel Cell and Other Cogeneration Systems CONTENT 1 Introduction General description of the two houses Meteorological data Data analysis Acknowledgements...Erreur! Signet non défini. 6 References Annexes page 31

32 Introduction This report aims at presenting the measurements and the analysis of electrical, domestic hot water (DHW) and space heating load profiles in two single family houses in Belgium (surroundings of Liege). These data have been monitored in the framework of the microcogeneration installation project Green Family [122] in order to create a database useful for the simulation and the performance assessment of cogeneration (CHP) systems within houses. This database is particularly useful to describe occupant-driven electrical and domestic hot water patterns. The household electricity consumption includes all domestic appliances: cooking, refrigerators, lightning, TVs, washing machines, PCs, miscellaneous appliances. The distinction between these diverse electric appliances hasn t been realized. When the DHW was produced by electricity, the DHW profile has been measured. The space heating load profile can be used to assess the simulation of house s thermodynamic model in conjunction with climate external conditions. In this respect, following climate parameters have been monitored: external temperature, sunshine radiation and wind velocity. All these data have been measured and stored with a 15 minutes time step. Energy profiles in the first house house A - have been monitored during one year (July 23 to June 24). The annual gas consumption for space heating was 4 Nm³ = 4 kwh energy and 67 Nm³ = 6 7 kwh energy for domestic hot water. The annual consumption of electricity was 11 5 kwh el.. Energy profiles in the second house house B have been monitored during 2 full years (22 and 23). The annual oil consumption was 2 litres = 2 kwh energy for space heating. The annual electricity consumption for appliances was 2 kwh el and the annual electricity consumption for domestic hot water was 4 kwh el. The two houses are presented, including the configuration and the basic control principle of their heating system, insulation materials and geometry. Systems that have been used to perform measurements inside the houses are briefly explained. In this respect, this report can be considered as a user manual of the database. The methodology used in Belgium (norm NBN B [114]) to determine the theoretical space heating demand in an existing or retrofitted house according to its geometry, insulation and location has been applied to both houses. Theoretical and measured space heating consumptions are then compared, as well as thermal conductivity coefficient. During one day, the electrical consumption has been measured in house B with a shorter time step (1 second) in order to evaluate the approximation that is introduced when the measurement is performed with a 15 minutes time step. Keywords: Field measurement, load profile, energy consumption, residential, Belgium, space heating, domestic hot water, electricity page 32

33 General description of the two houses House A General Characteristics [1] [3] [5] [7] [9] [11] [13] [15] [17] Building / Site Name Location Type Number of inhabitants Date Build Total floor area [m²] Heated floor area living area [m²] Heated volume ]m³] External walls [2] [4] [6] [8] [1] [12] [14] [16] [18] [19] [21] [23] [25] [27] Internal walls Floor between garage and ground floor Floor between ground floor and first floor Roof Windows [2] [22] [24] [26] [28] House A Liege, Belgium Single - detached Brick + vacuum + concrete block Concrete beam Wood beam + rock wool Slate + rock wool Wood -Double glazed Table 9 : General characteristics of the house A Heating System [29] [31] [33] [35] [37] [39] [41] [43] [45] [47] [49] [51] [53] [55] Building / Site Name System Fuel Type Power Production efficiency Delivery type Distribution of heat Electrical consumption for appliances Natural gas consumption for space heating Natural gas consumption for hot water % of dwelling mechanically ventilated? % of dwelling air-conditioned? DHW: type of energy source DHW tank volume [3] [32] [34] [36] [38] [4] [42] [44] [46] [48] [5] [52] [54] [56] House A Individual Boiler Natural gas 35 kw 9% (hypothesis) Radiators Water 11 5 kwh 4 Nm³16 of gas = 4 kwh 47 Nm³ of gas = 4 7 kwh % 25% Tank combined with the boiler 12 liters Table 1 : Heating system characteristics Schematics of the installation and control s principle In house A, a unique 35 kw boiler is used for both space heating and DHW heating. The boiler can either be ON or OFF. No power fluctuation is permitted with this boiler 16 Nm³ : cubic meter related to standard conditions : T=25 C, athmospheric pressure page 33

34 This boiler is firstly used for DHW heating: this is a priority. The thermostat in the 5 liters DHW tank controls the boiler and the DHW pump. Brown histograms on Figure 33 show the power used for DHW heating. When the boiler is used to heat the DHW tank, we can see that the measured outlet temperature (leaving temperature) is rising very fast, this is due to the fact that the temperature needed to heat the tank is higher than temperature needed for space heating When not used for domestic water heating the boiler can be used for space heating. The space heating pump is turned ON. The space heating is intermittent. Two periods can be manually defined via the regulator: a normal period and a reduced period. The period intervals are fixed and the power delivery is not optimized (usually: normal period: from 7 am to 11pm). Setup temperatures are defined for each period (18 C during the reduced period (night) and 24 C during the normal period (day), Figure 34). The boiler s control is done according to internal and external temperatures. The internal thermostat is used to determine if the rooms are to be heated or not. This explains why the boiler is generally turned off during the reduced period (night). Nevertheless an exception is made for colder days in winter when the indoor temperature drops under the reduced wished temperature. The external temperature is used to determine the heating curve (Figure 32). The boiler is turned on when the boiler s leaving temperature is lower than the temperature given by the heating curve minus a differential and vice versa. The boiler is very often started up and shut down in order to maintain the temperature of the heating loop close to the heating curve level until the internal setup temperature is reached. With this control principle, the goal of the boiler is not to maintain a level of temperature in the rooms. The boiler can be turned off even if the internal setup temperature isn t reached or the boiler can continue to work even if the internal setup temperature is reached. This explains why the wished temperature may sometimes not be attained or may be over passed as shown on Figure 34. The Figure 33 shows that the boiler s outlet temperature is depending on the evolution of the external temperature. The temperature of the water leaving the boiler in house A is clearly following the heating curve. The temperature of the water at the outlet of the boiler can reach 7-8 C in order to feed the radiators for the house A in winter. The morning s start demand is clearly identified from 7 o clock. This important amount of energy is due to the increase of the set point in the rooms (from 18 C to 24 C). During the restart of heating, the boiler typically works during a long period without stopping. The internal temperature rises. The electrical consumption profile is largely influenced by the occupancy pattern as seen on Figure 35. The consumption is higher during the evening or the lunch. We must note that an air-conditioning system has been installed to cool down upstairs bedrooms in summer. Unfortunately, the electric consumption for this system isn t dissociated from other electric appliances consumptions. page 34

35 Figure 31: Schematics of the installation in house A Figure 32: heating curve 29/3/24 House A : Total power of the boiler Average external temperature = 6.37 C Average boiler's total power kw Thermal power(kw) Temperature ( C) Hour Power for space heating Power for Domestic Hot Water heating Internal temperature (T1) External temperature (T2) Boiler's inlet temperature (T3) Boiler's outlet temperature (T4) -15 Figure 33: Space heating control s principle page 35

36 29/3/24 House A : Power for space heating Average external temperature = 6.37 C Average power for space heating kw Thermal power(kw) Temperature ( C) Hour Power for space heating Internal temperature (T1) Figure 34: Space heating regulation 29/3/24 House A: Electrical consumption Average electrical consumption = 2.34 kw Electrical consumption (kw) Heure Electrical consumption Figure 35: Electrical consumption Measured data The following data have been measured during one year (from July 23 to June 24) with a 15 minutes time step: - Internal temperature (T1) (in the living-room); - External temperature (T2) (west side of the house, sheltered from sunshine) - Boiler s inlet temperature (T3); - Boiler s outlet temperature (T4); - Total electrical consumption; - Operating time of the boiler during the 15 minutes, allowing us to calculate total gross energy for both space and DHW heating; - Operating time of the space heating pump and the DHW pump allowing us to dissociate the gross space heating power and the gross DHW heating power Temperatures have been measured with PT1 (3 wires) sensors. The electrical consumption of the house has been measured with a photo electric cell. This cell has been installed on the general electric meter (Figure 36). It detected and closed an electrical contact each time 1/12 kwh was consumed. The thermal power delivered by the boiler to the radiators and/or to the domestic heat stock was measured using relays on the supply voltage of the gas valve, the space heating pump and the DHW pump. page 36

37 Figure 36: photo electric cell and PT1 sensor page 37

38 House b General characteristics [57] [59] [61] [63] [65] [67] [69] [71] [73] Building / Site Name Location Type Number of inhabitants Date Build Total floor area [m²] Heated floor area living area [m²] Heated volume [m³] External walls [58] [6] [62] [64] [66] [68] [7] [72] [74] [75] Internal walls [77] Floor between garage and ground floor House B Liege, Belgium Single - detached Stone + vacuum + YTONG block [76] [78] Concrete beam + argex marble [8] Wood beam + rock wool [82] Slate + rock wool [84] Wood -Double glazed [79] Floor between ground floor and first floor [81] Roof [83] Windows Table 11 : General characteristics of the house A Space heating and DHW general description [85] [87] [89] [91] [93] [95] [97] [99] Building / Site Name System Fuel Type Power Production efficiency Delivery type Distribution of heat Electrical consumption (av. per year) [11] Normal Oil consumption [13] Normal Energy consumption [15] % of dwelling mechanically ventilated? [17] % of dwelling air-conditioned? [19] DHW: type of energy source [111] DHW tank volume [86] House B [88] Individual Boiler [9] Oil [92] 2 kw [94] [96] Radiators [98] Water [1] 16. kwh + 4. kwh for DHW [12] 25 liters [14] 2. kwh for space heating [16] % [18] % [11] Tank with electrical element (3 kw) [112] 2 liters Table 12: Heating system characteristics page 38

39 Schematics of the installation and control s principle In this house, a 2kW boiler is used for space heating. The DHW is produced in a separate 2 liters tank. A 3kW electrical element is the source of heat in this tank. The Figure 37 presents the schematics of the installation. The space heating is intermittent. Two periods can be manually defined via the regulator in the living room: a normal period and a reduced period. The period intervals are fixed and the power delivery is not optimized (usually: normal period: from 6 am to 11pm). Setup temperatures are defined for each period (18 C during the reduced period and 24 C during the normal period; see on Figure 38). The control of the boiler s status is only done according to the internal temperature. No external sensor is used to regulate the system. The boiler can either be ON or OFF. No power fluctuation is permitted with this boiler. The principle used to turn on and off the boiler relies on a simple relay with threshold and a differential. It acts as a thermostat. The boiler is turned on when the internal temperature is lower than the lower threshold and turned off when the internal temperature is higher than the higher threshold. The boiler is turned on and isn t shut down until the internal setup temperature isn t reached. This control strategy leads to larger fluctuations in the circuit s temperature than system in house A but tends to be more dynamic and more able to restore the wished internal temperature. During the restart of heating, the boiler typically works during a long period without stopping (one half hour to 2 hours). The internal temperature rises until it reaches the setup temperature. This delay of rising depends on the indoor temperature and on the heating load. The restoring of the temperature in the house B is better achieved than in house A. This seems to be due to the control of the boiler. During the night, the boiler is generally turned off but for colder days. An important point to note is that the DHW tank is only heated during low electrical tariff periods. As we will see further, neither in house A nor in house B have we been measuring the consumption but the production. This must be kept in mind when analyzing these data. In addition, we should have measured the water flow rate and the outlet temperature of the DHW to reflect more accurately the DHW profile. The household electrical consumption includes all electrical appliances apart from DHW heating page 39

40 Figure 37 : Schematics of the installation in house A. House B: Boiler regulation 13/2/23 Average power of the boiler reduced differential normal Internal temperature Hour Power of the boiler Internal temperature (T1) Figure 38 : Space heating control principle page 4

41 House B: electrical consumption Electrical consumption (kw) = /2/23 DHW consumption (kw) = kw : 1: 2: 3: 4: 5: 6: 7: 8: 9: 1: 11: 12: 13: 14: 15: 16: 17: 18: 19: 2: 21: 22: 23: P without DHW P DHW Figure 39 : Electrical consumptions for appliances and DHW Measured data and system used for measurements The following data have been measured during two years (22 and 23) with a 15 minutes time step: - Internal temperature (T1) (in the living-room); - External temperature (T2) (west side of the house, sheltered from sunshine); - Boiler s temperature (T3); - Total electrical consumption; - Operating time of the boiler during the 15 minutes, allowing us to calculate gross space heating power; - Operating time of the electrical element in the DHW tank, allowing us to calculate the DHW; Temperatures have been measured with PT1 (3 wires) sensors. The electrical consumption of the house has been measured with a photo electric cell. This cell has been installed on the general electric meter. It detected and closed an electrical contact each time 1/12 kwh was consumed. Knowing the number of time this contact has been closed during the 15 minutes time step allowed us to calculate the electric consumption. The thermal power has been derived from the operating time of the boiler assuming a constant power. The operating time of the boiler has been calculated using a relay on the supply voltage of the burner s valve. Another relay has been installed on the power supply of the DHW tank s electrical element. Note that this last procedure was not optimal and should be improved if future measurements were to be done. It should have been of primary importance to measure the domestic hot water consumption (in liters) via a water flow meter in addition to the electrical consumption. This improvement is particularly true in this house B where the DHW tank was particularly big and DHW was heated by electricity during low tariff periods A data logger was used to make these measurements. Data in the data logger were to be downloaded approximately once a month. page 41

42 Comparison We have used the following indicators to compare the energy consumptions of houses Energy criteria (Figure 41) o Primary energy o Final energy (energy delivered to the building as fuel, heat or electricity) o Useful energy (energy supplied by the HVAC system to cover the net energy demand for space heating/cooling, DHW and electricity respectively = net energy) CO2 criteria The primary energy factors (primary energy to final energy) were determined from the CWAPE procedure used in Belgium. Two sets of CO2 emissions factors (CO2 to final energy) were used. The first one is determined from the CO2 calculation procedure used in Belgium [124] 17. The second one is based on the European mix according to UCTE [125]. Figure 4: Useful, final and primary energy [125] Space heating demand and space heating measured energy We have applied the Belgian norm NBN [114] to calculate the annual space heating demand according to the geometry, insulation and location for both houses that are described in annex 1. The dedicated program DENIBE [117] was used to compute the calculation. Simulation results are given in the first column for house A of Erreur! Source du renvoi introuvable. and in the third column for house B. We have add the measured data in column 2 for house A, and in column 4 and 5 for house B. The simulated value for the space heating energy consumption is relatively close to the measured one: line 12 and 15. The total energy consumption [kwh/year]for space heating isn t the only indicator to compare houses. In Belgium, the net heating needs parameter Be [MJ/m².year] (line 11) is usually used to compare the consumption of houses and define categories and the energy level reached by houses. When simulated, this value takes into account a typical year and calculates the number of degree days of this year (line 1). This calculation includes the internal gain, solar factors, etc When measured, the net heating needs parameter Be [MJ/m².year] (line 11) doesn t allow us to separate the effect of the energy consumption level and the effect of 17 For electricity: 456 kg CO2/MWh final; NG: 251kg CO2/MWh final; Oil: 36 kg CO2/MWh final. These figures are based includes the extraction, conversion, transportation and combustion of the fuel (based on LHV) page 42

43 the external temperature. Comparing 2 houses during 2 different periods seems not relevant with this parameter. How can we separate the effect of thermal insulation and the climate conditions? Another parameter is used then: the net heating needs P [W/m²K] (line 9). This parameter show that the house A is more energy consuming than house B. Note that a passive house can be defined by a net heating needs parameter P less than.15 [W/m²K]. From an external point of view, both houses seem quite similar (single detached, same external dimension, same total floor area) but they are in fact quite different: - The energy consumption [kwh/year] for space heating in house A is twice as much as in house B (see line 12); - The electrical consumption [kwh/year] for appliances is smaller in house A than in house B; - The house A has a bigger heated floor area and a bigger heated volume than house B; - Concrete blocks are used for external walls in house A when Ytong blocks are used in house B leading to a better insulation; - An air-conditioning system is installed in house A for the summer; - Heating systems and the regulation of boilers are different (as seen above). The Figure 41 shows the comparison of both houses according to the primary energy consumptions. Although the energy consumption for space heating is greater in house A than in house B, this is compensated by the bigger electrical consumption. The useful energy consumption of house B is bigger than house A but the primary energy consumption is quite similar The Figure 42 presents the CO2 emissions of both houses. It can be seen that both house have similar CO2 emissions level. Building / Site Name House A simulat ed House A 7/3-6/4 House B simulat ed Space heating Total floor area [m²] Heated floor area living area [m²] Jacket surface (defined by the heated volume) [m²] Heated volume [m³] Global thermal conductivity coefficient ks [W/m²K] 18 Global thermal conductivity coefficient k [W/K] Global thermal insulation coefficient K Net Heating needs P [W/K] Net heating needs to heated surface P [W/m²K]Erreur! Signet non défini. = (8)/(2) or (13)*(1) House B 22 House B Degree days Related to the surface defined by the heated volume (jacket surface or loss surface). In [115], J. Schnieders defines the basic idea of a passive house and specifies the range of the ks coefficient between,1 and,15 W/(m²K) 19 This coefficient must be less than 55 in new houses to fullfill insulation performance laws. 2 Including ventilation page 43

44 Net heating needs Be [MJ/m².year] 21, Annual space heating demand [kwh/a] = (11)*(2)/3.6 Annual space heating demand per heated surface [kwh/m².a] = (11)/3.6 Annual useful energy for space heating [kwh/a] Annual final energy for space heating [kwh/a] Domestic hot water Annual final energy for DHW [kwh/a] Annual useful energy for DHW UD DHW [kwh/a] Electricity Annual useful electrical consumption UD El [kwh/a] Table 13 : comparison between houses Figure 41 : Useful, final and primary energy consumptions Comparisson of CO2 emissions 25 CO2_CWAP E CO2_UCTE CO2_CWAP E CO2_UCTE CO2_CWAP E CO2_UCTE 2 Annual CO2 emissions (kg CO2) house A 23/24 house B - 22 house B - 23 Electrical appliances DHW by electricity Space heating by boiler (gaz or oil) DHW by boiler Figure 42: Annual CO2 emissions (CWAPE coefficients vs UCTE coefficients) 21 Related to the heated floor surface 22 Assuming 2248 degree days per year for house A and 1938 degree days per year for house B - 23 Number of liters of oil (or m³ of natural gas) burnt in the boiler during one year translated in kwh 1 m³ gas = 1 liter of oil = 1 kwh 24 Hypothesis: Space Heating: efficiency of the boiler and distribution : 9% 25 Hypothesis: DHW heating : boiler efficiency (house A) : 9% - DHW electrical element efficiency (house B) : 1% page 44

45 Meteorological data Introduction the climate in Belgium Belgium (Figure 43) is a country of lowlands and low plateaus. Three topographic regions, based on elevation, can be distinguished. Low Belgium includes all the lands along the North Sea coast and the northern border with the Netherlands. Middle Belgium occupies the central part of the nation between the sandy hills of Flanders and the Campine and the industrial towns of Mons, Namur, Charleroi, and Liege, which are located in the Sambre-Meuse Valley. High Belgium occupies the region south of the Sambre-Meuse Valley. It includes the rolling hills of the Condroz Plateau, which forms a belt of farmlands south of the industrial valley, and the heavily forested Ardennes, an old mountain range now reduced to low, rounded summits and deep, winding valleys. Many of the summits of the Ardennes have elevations of more than 5 m and include the country s highest peak. Belgium has a temperate marine type of climate, which is characterized by a narrow range of temperatures between summer and winter. High Belgium, located farther from the sea, has a more extreme, continental type of climate. The climate of the entire country is dominated by cyclonic storms associated with the westerly wind belt and is extremely variable. The mean temperature in January varies from 3 C on the coast to -2 C in the Ardennes. In July the mean temperature is 16 C along the coast and 15 C in the Ardennes, but can reach 18 C in the center of the country, the cooler Ardennes temperature being the result of elevation. The number of days in the year of frost is 4 on the coast and 12 in the Ardennes. Average annual precipitation is 78 mm in Brussels, 65 mm in coastal areas and 1,45 mm in the more elevated Ardennes. The number of days when snow is recorded increases from 6 along the coast to 32 in the Ardennes source : [12] - [121] Figure 43: Maps of Belgium Measured parameters The three following meteorological parameters have been recorded (with 15 min time step) in order to evaluate their effects on the energy consumptions of both houses: external temperature, solar irradiation and wind velocity. The external temperature has been measured for each house. The other two parameters (solar irradiation and wind velocity) have been recorded in the meteorological station of the University of Liege, located close to the 2 houses (5 kilometers). The solar irradiation values represent the solar intensity received on a horizontal plane (unit W/m²). The wind velocity values are given in meters/second. Figure 44 to Figure 46 show the evolution of these daily mean parameters over year 23. page 45