MATO GROSSO STATE UNIVERSITY – UNEMAT
URSULA MAIRA MACIEL RIGON
DEVELOPING A HOME ACCORDING TO THE SOLAR DECATHLON
COMPETITION UNDER CUIABÁ CLIMATE
SINOP - MT
2016/2
MATO GROSSO STATE UNIVERSITY – UNEMAT
URSULA MAIRA MACIEL RIGON
DEVELOPING A HOME ACCORDING TO THE SOLAR DECATHLON
COMPETITION UNDER CUIABÁ CLIMATE
Research project presented to the examining board of the Civil Engineering Course - UNEMAT, University Campus of Sinop-MT, as a prerequisite to obtain a bachelor's degree in Civil Engineering. Supervisor: Dr.-Ing. Marlon Leão
SINOP - MT
TABLE LIST
Table 1: Contests and Scores ... 12
Table 2: Contests, Subcontests and Scores... 13
Table 3: Jury Classes to Place the Teams ... 14
Table 4: Energy Price ... 18
Table 5: Passive Strategies ... 19
Table 6: Authors that used SWH for DWH in the SD ... 24
EQUATIONS LIST
Equation 1: Required Capacity Installed ... 21 Equation 2: Area of PV Panels ... 22
FIGURES LIST
Figure 1: Schematic PV System ... 20
Figure 2: Tilt Angle of PV Panel ... 21
Figure 3: Cronemberger et al. (2014) Study ... 23
Figure 4: Schematic SHW System ... 25
Figure 5: Flowchart Phase One ... 30
ABREVIATIONS LIST
US DOE – United States Department of Energy NZEB – Net Zero Energy Building
SD – Solar Decathlon
NEEP – National Energy Efficiency Plan PV – Photovoltaic
BAPV – Building Applied Photovoltaic BIPV – Building Integrated Photovoltaic DHW – Domestic Hot Water
SWH – Solar Water Heater
HVAC – Heating Ventilation and Cooling EV – Electric Vehicle
IRC – International Residential Code NEC – National Electric Code
NFPA – National Fire Protection Agency WWR – Window to Wall to Ratio
SDC – Seismic Design Category AC – Alternating Current
DC – Direct Current
IDENTIFICATION DATA
1. Title: Developing a Home According to the Solar Decathlon Competition 2. Theme: Civil Engineering (30100003 CAPES)
3. Delimitation of the Theme: Construction (30101000 CAPES) 4. Proponents: Ursula Maira Maciel Rigon
5. Advisor: Dr.-Ing. Marlon Leão
7. University: Mato Grosso State University
8. Target Audience: Students, teachers, researchers and professionals in the
field of civil construction.
9. Address: Ingas Avenue 3001, Sinop – MT. Zip code: 78550-000 10. Duration: 12 months
SUMMARY
TABLE LIST ... I EQUATIONS LIST ... II FIGURES LIST ... III ABREVIATIONS LIST ... IV IDENTIFICATION DATA ... V
1 INTRODUCTION ... 8
2 STATEMENT OF THE PROBLEM ... 9
3 JUSTIFICATION ... 10
4 OBJECTIVE ... 11
4.1 GENERAL OBJECTIVE ... 11
4.2 SPECIFIC OBJECTIVES ... 11
5 LITERATURE REVIEW ... 12
5.1 SOLAR DECATHLON CONTESTS... 12
5.1.1 Architecture ... 14 5.1.2 Market Potential ... 14 5.1.3 Engineering ... 15 5.1.4 Communications... 15 5.1.5 Innovation ... 15 5.1.6 Water ... 15
5.1.7 Health and Comfort ... 15
5.1.8 Appliances ... 16 5.1.9 Home Life ... 17 5.1.10 Energy ... 17 5.2 MAIN STRATEGIES ... 18 5.2.1 Building Envelope ... 18 5.2.2 Photovoltaic System ... 19
5.2.3 Hot Water System ... 24
5.2.4 Heating Ventilation and Cooling – HVAC System ... 25
5.2.5 Lightning ... 26
5.2.6 Appliances and Electronics ... 27
5.2.7 Commuting ... 27
5.3 SOFTWARES ... 28
5.3.1 AltoQi ... 28
5.3.2 AutoCAD ... 28
5.3.4 SketchUp ... 29 6 METHODOLOGY ... 30 6.1 PHASE ONE ... 31 6.1.1 Architectural ... 31 6.1.2 Engineering ... 32 6.1.3 Water ... 33 6.1.4 Appliances ... 34 6.1.5 Home Life ... 34 6.2 PHASE TWO ... 34
6.2.1 Health and Comfort Simulation ... 35
6.2.2 Energy Simulation ... 35
6.2.3 Energy Balance Analysis ... 35
6.2.4 Market Potential Analysis ... 36
6.2.5 Home Final Score ... 36
7 EXPECTED RESULTS ... 37
8 SCHEDULE ... 38
1 INTRODUCTION
It has been observed in the recent years that the residential building sector has presented high contribution to the energy demand, approximately 40% (ADHIKARI et al., 2012). Two facts can explain this growth; one is due to the electricity access for new house-holds, and the other is due to the home equipment and technologies, and to the users’ behavior (KOS; SOUZA, 2014). Because the high energy demand contributes to the global warm and to the inevitable exhaustion of non-renewable energy sources, the energy efficient buildings have become increasingly important to the modern construction industry.
Many laws and action plans has been created by governments to improve this situation. The United States Department of Energy – US DOE, created in 2000 the US Zero Net Energy Building Outreach and the Action Plan wich aims to build over 100,000 net zero energy buildings – NZEB by 2020 in the country. To reach the goal, the Solar Decathlon was one of the two efforts created (CHARRON, 2005). The Solar Decathlon – SD is a biennial competition first held in Washington DC City – 2002. The competition encourages teams to project an energy efficient house with attraent design and low cost budget. The SD promotes research and development of new energy strategies, and also, it promoves world consciusness in the sustainability point of view.
In the Brazilian scenario, the actions to reduce energy demand started in 2001 with the energy rationing. Since then, there was created the equipment energy efficiency label (PROCEL), and the replacement of incandescent lamps for fluorescent in the market. The National Energy Efficient Plan - NEEP is the most recent action (2011), which aims to reduce the residential energy demand from 42.1% to 15.7% by 2030 (GOVERNO FEDERAL MINISTÉRIO DE MINAS E ENERGIA, 2014).
2 STATEMENT OF THE PROBLEM
The obsolete way of construction, which is nowadays outdated and inadequate, has been resulting in a growth of energy demand. Therefore, instead of reducing energy consumption, households spend more energy each year. Since 1990, the average grown in the residential electricity consumption is 3.4% per year (KOS; SOUZA, 2014).
It has been observed that developed countries have created governmental plans and goals to change this scenario. On the other hand, those planning are not observed in Brazil with same efforts. Despite the Brazilian Government created in the recent years target numbers of energy reduction, there isn’t any concrete actions to make it possible to achieve the goals established.
3 JUSTIFICATION
Energy efficient building has turned a priority in the recent years due to the growth of residential energy consumption and CO2 emissions. Many countries have
been developing new buildings regulations, actions and plans to encourage construction of high energy performance buildings. The Solar Decathlon competition is one of the US DOE efforts to achieve the reduction of residential energy consumption in the US country. According to Kos & Souza (2014), the SD was created with three main purposes:
(1) Educate academic students and the public about environmental benefits and design solutions presented by clean-energy products, and also, demonstrated the money-saving opportunities from it;
(2) Exhibit that energy efficient homes and appliances with renewable energy system can present comfortable spaces and affordability project;
(3) Prepare students and professionals with unique knowledge to enter the nation’s clean-energy workforce.
The implementation of the SD competition in the Brazilian academic environment would help the country to develop new clean energy strategies and technologies, would encourage professionals to adequate old construction habits concerning sustainability point of view, and would educate the public about the energy efficiency benefits. As a final result of all advantages from SD, it would help to achieve the NEEP goal in reduce energy demand from 42.1% to 15.7% by 2030, and to promote a significant change in the residential constructions techniques.
4 OBJECTIVE
4.1 GENERAL OBJECTIVE
Development and analysis of a residence project according to the Solar Decathlon rules and requirements.
4.2 SPECIFIC OBJECTIVES
Analyze health and comfort performance of the house; Assessment of house energy balance;
Determination of house market potential;
5 LITERATURE REVIEW
5.1 SOLAR DECATHLON CONTESTS
The SD has been fulfilling their goals and spread them out around all the world. Since its first version, it has been held six times in the US, three times in the Europe, once time in China, once in Latin American and Caribbean. Also, it is confirmed to happen in the United Arab Emirates by 2018, and in Africa by 2019. The competition totalized until now 224 teams and 32500 involved students around the
world (SOLAR DECATHLON: INTERNATIONAL SOLAR DECATHLON
COMPETITIONS, 2017).
The Solar Decathlon Building Code adopted as reference the 2012 International Residential Code (IRC) of the International Code Council and the 2014 National Electric Code (NEC) of the National Fire Protection Agency (NFPA) to base their rules and requirements.
The Solar Decathlon scores the houses in a 10 separately contests, some contests have one or more subcontests. The evaluations consist in two ways, some of them are evaluated by a jury of specialized professional in the respective field, and some of them are evaluated by task completions and monitored performance. Each contest worth up to 100 points, and the team with the highest sum of points wins the competition (DECATHLON; RULES, 2016). The contests, subcontests and their respective points are showed in the table 1 and 2.
Table 1: Contests and Scores Juried
Contest Number Contest Name Points
1 Architecture 100 2 Market Potential 100 3 Engineering 100 4 Communications 100 5 Innovation 100 6 Water 100
Juried Total 600 Source: Decathlon & Rules (2016)
Table 2: Contests, Subcontests and Scores Measured
Contest Number
Contest
Name Points Subcontest Name Points
Tasks or Periods 7 Health and Comfort 100 Temperature Humidity Indoor Air Quality
Air Tightness 55 25 10 10 588 588 320 1 8 Appliances 100 Refrigerator Freezer Clothes Washer Clothes Drying Cooking Hot Water 8 8 10 20 12 42 766 766 5 5 6 14 9 Home Life 100 Lighting Home Electronics Dinner Party Game Night Commuting 30 10 10 5 45 30 20 2 1 5 10 Energy 100 Energy Production Energy Value 60 40 - - Measured Total 600 Total 1000
The first six contests will be evaluated trough deliverable review and by on-site walkthrough. The jury will place each team in one of the four classes in the table 3.
Table 3: Jury Classes to Place the Teams
Class 1: ECLIPESES 91% 100% of available points
Class 2: EXCEEDS 81% 90% of available points
Class 3: EQUALS: 61% 80% of available points
Class 4: APPROACHES 0 60% of available points
Source: Decathlon & Rules (2016)
For the other contests, the team earns all points if it meets all requirements. In some cases, when a part of requirements is met the team can collect reduced points.
5.1.1 Architecture
The architecture contest is evaluated by a jury of architects that will assign an overall score considering the concept and design approach, the architectural implementation and innovation, the documentation and presentation of the house (DECATHLON; RULES, 2016). In this contest, the interest is the attractive design, which it should combine comfortable and functional spaces, bioclimatic technologies and strategies of energy efficiency, also, a coherent and comprehensive project (MATALLANAS et al., 2014). For the dimensions’ requirements, the SD has: the finished square footage of the house shall be between 600 ft² and 1000 ft² (55 m² and 93 m²), the constructed footprint cannot exceed 2,700 ft² (250 m²), and the ceiling height shall be at least 7ft (2 m) of headroom (DECATHLON; RULES, 2016). Stairs are not permitted, in case of change of elevation ramps should be used with maximum of slope of 1:12 and including handrails (PALATINE (ILL.), 1976).
5.1.2 Market Potential
It is evaluated by professionals from the homebuilding industry. The criteria for this contest is the market potential, livability, cost effectiveness and buildability of the house. The main concern in this contest is to determine the attractiveness of the house to the industry. The budget permitted for the cost
construction is between $250000 (R$100000) and $600000 (R$180000), an amount lower than $250000 collected all points, between the range it earns scaled linearly points, and above $600000 no points are gained (DECATHLON; RULES, 2016).
5.1.3 Engineering
The engineering contest is evaluated by a jury of engineers. The criteria will consider the approach, design, efficiency, performance and documentation of the house (DECATHLON; RULES, 2016). All the elements of the house, from structure building to its energy systems will be analyzed (MATALLANAS et al., 2014). The dimensioning of the structural plan should consider: wind 85mph (136 km/h), exposure category C; seismic IRC Seismic Design Category (SDC) D; railings of 200lb (90 kg); live load for interior floor, decks and ramps of 50psf (244 kg/m²), for exteriors 100psf (488 kg/m²); roof live load of 20psf (97 kg/m²), and temporary paved surface of 6000psf (29300 kg/m²). For the ground anchorage, the stake capacity can be assumed as: 1250 pounds’ vertical withdrawal (567 kg); and 1500 pounds’ horizontal shear (680 kg), (PALATINE (ILL.), 1976).
5.1.4 Communications
A jury of communications professionals will score considering strategy, implementation and on-site communications criteria. Team’s communication strategies, materials and efforts to educate, inform and interest the public are the matter in this contest (DECATHLON; RULES, 2016).
5.1.5 Innovation
A jury of industry professionals will consider research, sustainability and innovation criteria to score. In this contest the team has to be able to apply innovation in concept, approach, research, design, implementation and execution (DECATHLON; RULES, 2016).
5.1.6 Water
It is evaluated by industry professionals that will analyze conservation, reclamation and reuse, and landscaping criteria. The worry in this contest is about the smart conservation, use and reuse of water (DECATHLON; RULES, 2016).
This contest score by the measuring of interior temperature, interior humidity, indoor air quality and air tightness. All points are earned if the time-averaged interiors dry-bulb temperature ranges from 68°F to 74°F (20°C to 23°C). Reduced points are earned if it ranges from 74°F to 78°F (23°C to 25°C), or from 64°F to 68°F (17°C to 20°C). Temperatures below 64°F (17°C) or above 78°F (25°C) score no points. For the humidity, all points are collect if it ranges from 35% to 60%. Reduced points are collected if it is between 25% and 35%, or between 60% and 70%. Humidity below 35% or above 70% collects no points. Indoor air quality gains all points by keeping the interior CO2 level below 1000 PPM (parts per million).
Ranges from 1000 to 2000 PPM (998.85 mg/l to 1997.72 mg/l) gain reduced points, and above 2000 PPM (1997.72 mg/l) no points are collected. To conclude, air tightness earns all points if it is less or equal to 0.05 CFM 50/ft² (1 ACH – 50Pa). Reduced points are earned if the measurement is between 0.05 and 0.25 CFM 50/ft². Values above 0.25 CFM 50/ft² earns no points (DECATHLON; RULES, 2016).
5.1.8 Appliances
In this contest the house has to be able to maintain the refrigerator, the freezer, the washing machine, the clothes dryer, the cooking and the hot water working properly. The refrigerator earns all points by keeping its interior temperature between 34°F and 40°F (1°C to 4.5°C). For temperatures between 32°f and 34°F (0°C to 1°C) or between 40°F and 42°F (4.5°C to 5.5°C), it gains reduced points, and below 32°F (0°C) or above 42°F (5.5°C) no points are collected; also, the refrigerator shall be a minimum volume of 4.5ft³ (1.3 m³). The freezer task earns all points if it keeps your interior temperature between -20°F and 5°F (-29°C to -15°C). Reduced points are gained if it ranges from -30°F to -20°F (-34°C to -29°C), or from 5°F to 15°F (-15°C to -9.5°C); the required freezer volume shall be a minimum of 2 ft³ (0.05 m³). The washing machine earns all points if it runs normally with no interruption one or more cycles to wash six organizer-supplied bath towels. The clothes drying task collects all points if it returns the total weight of the towels equal or less than before being washed, reduced points are earned if the towels volume ranges from 100% to 110% of the original weight. Volumes higher than 110% gain no points; also, the clothes dryer must work with no interruption too. In case of the team use natural drying method, it must be demonstrated into the architecture and market potential contests. The cooking task earns all points if its appliance is able to vaporize 5lb of
water (2.25 kg). Reduced points are collected if it vaporizes between 1lb and 5lb (0.5 kg to 2.25 kg); the container to vaporize must be a single one and the starting weight shall be at least 6lb (2.7 kg). The team is eligible for points in the hot water task if the house deliveries in no more than 10 minutes a minimum of 15 gal of hot water (57 l). All points are gained if the water temperature is equal or above to 110°F (43°C), if it ranges from 100°F to 110°F (37°C to 43°C), reduced points are earned (DECATHLON; RULES, 2016).
5.1.9 Home Life
This contest evaluates the home lighting, the home electronics, the success in host two dinners party and in host a game night, and commuting. The lighting collects all points if the measurements are 300lux or greater in all of the four spaces chosen. Illumination levels between 300lux and 100lux earns reduced points. For home electronics, the team collects all points if the house operates according to the schedule, a television with minimum display of 27 in (68.6 cm), and a computer with a minimum display of 15 in (38 cm). They have to work continuously and simultaneously, the brightness of both displays shall be at least 75% and the electronics have to be plugged in a single organizer. The dinner party involves a pair of decathletes and up to two VIP guests. The team earns all points if it prepares beverages and a complete meal in the house according to the schedule. The team has also to serve the dinner with adequate temperatures and in a timely manner, and the room space used has to be conditioned. Game night also involves a pair of decathletes and up to two VIP guests. To gain all points the room space used has to be conditioned, they have to supply board or card games, and the food and drinks served shall be according to the safety requirements defined. To conclude, the commuting earns all points by driving at least 25 miles (40 km) in no more than 75 minutes. If it drives less than 25 miles, linearly points will be collected. In addition, the vehicle has to be charged from the house electric system, and its battery must be full at the completion of the contest (DECATHLON; RULES, 2016).
5.1.10 Energy
This contest evaluates the energy production and the energy value. All points are earned for energy production if its final electrical energy balance is at least 0 kWh, reduced points are collected for ranges from -50 kwh and 0 kWh, no points
are gained if it is below -50 kWh. The energy value collects all points if the energy calculated at the conclusion of energy period is less or equal to $10 (R$26), above it no points are earned. The calculation of the energy value can be observed in table 4 (DECATHLON; RULES, 2016).
Table 4: Energy Price
Rate Name Off-Peak Morning-Peak On-Peak Afternoon- Peak Off-Peak
Time Period 12 am – 7 am 7 am – 1 pm 1 pm – 7 pm 7 pm – 10 pm 10 pm – 12 am Net consumption cost per kWh $0.05 $0.12 $0.45 $0.15 $0.05 Net production value per kWh $0.00 $0.05 $0.20 $0.08 $0.02
Source: Decathlon & Rules (2016)
5.2 MAIN STRATEGIES
To design a NZEB, it is primordial to optimize the main systems and elements of the home applying energy efficient strategies. The state-of-art is going to be discussed based on authors references in the following aspects: building envelope, photovoltaic system, hot water system, heating, ventilation and cooling system, lightning, appliances and electronics, and at last commuting.
5.2.1 Building Envelope
The envelope is considered to be the skin of a building (YUN et al., 2010). It is a challenge to design a satisfactory envelope to the SD competition because it should satisfy three points of view. Concerning the construction point of view, it has to transport and to assembly and disassembly easily. Concerning the architecture it has to be attractive, and for the last, concerning the engineering it has to satisfy the thermal comfort conditions (WANG, N. et al., 2009).
Looking only into the thermal comfort aspect, the envelope is the main source for the thermal loads and for daylighting (PEDRINI; WESTPHAL; LAMBERTS, 2002). To optimize a high performance facade, the passive strategies are the most suitable
method. The passive strategies are the passive designs that increase the energy efficiency and contribute to the interior thermal comfort and lighting conditions (RODRIGUEZ-UBINAS et al., 2014). There are passive strategies suitable for: envelope, heating, cooling, spacing planning and exteriors, and hybrid systems. The table 5 summarizes the most used passive strategies for each aspect.
Table 5: Passive Strategies
Envelope
Low thermal transmittance Out/Inside insulation
Ventilate façade Air tightness
High performance glazing Optimized Orientation/Form
Passive Heating
Passive solar gain Double skin glass facade
Sunspace (glass balcony, glass terrace)
Passive Cooling
Fixed solar shading Natural ventilation
Night ventilation
Passive Space Planning and Exteriors
Vegetation Wetland
Living areas north oriented
Hybrid Systems
Ventilation heat recovery Evaporative cooling Night cooling ventilation
Radiant floor/ceiling Ground heat exchanger
Mobile solar shading Source: Rodriguez-Ubinas et al. (2014)
To achieve a satisfactory envelope, the home model needs to be optimized by simulation, considering different system and passive strategies applied, in order to get the solar gains, heat loss and daylight desirable (YUN et al., 2010).
5.2.2 Photovoltaic System
The photovoltaic technique, is known as the best method to convert solar energy, because it can directly convert the sunlight into electricity without any help from heat engines (ZHOU et al., 2016). Even though, the differences in climatic conditions around the world, the photovoltaic - PV panels can be used in almost
anywhere (ADHIKARI et al., 2012). As a matter of fact, since the 80s of last century when the first NZEB prototypes was built, it can be observed that the PV panels has a major role, being satisfactory for most of all energy needs (ADHIKARI et al., 2012). For the SD scenario it is not different, the sunlight is the main renewable energy source converted in electric energy by the PV panels.
A PV system is composed by a PV panel, a PV inverter, the distribution board and the storage battery. Figure 1 shows a PV schematic system.
Figure 1: Schematic PV System Source: Iimura; Yamazaki; Maeno (2014)
To dimension a PV system, it is necessary to first calculate the energy demand from the home (ADHIKARI et al., 2012). Zhang et al. (2014) calculated all the load demand from the lightning, appliances, electronics, HVAC system and DWH system, in order to dimension its PV panels. For the appliances and electronics, Invidiata & Mizgier (2013) estimated an schedule with each appliance/electronics, power (W), and time of use/day (h), in order to calculate the heat load and the energy demand from them. Once the energy demand is calculated, it is necessary to identify the local site of the home and which PV panel is going to be used, in order to get the local solar irradiance and the PV panel power. The local solar irradiance lean on the
tilt angle of the PV panel, which can be simulated in order to get the most suitable one. Figure 2 illustrates the tilt angle of a PV panel.
Figure 2: Tilt Angle of PV Panel Source: Chandra Mouli; Bauer; Zeman (2016)
With the solar irradiance, the energy demand and the PV panel power, it is possible to calculate the required capacity installed by the equation (1).
𝑃𝑚𝑝𝑝 = 𝑊𝑒𝑙𝑥1𝑘𝑊/𝑚²
𝐸𝑔𝑙𝑜𝑏, 𝑠𝑜𝑙, 𝑝𝑎𝑛𝑒𝑙𝑥𝑓𝑝𝑜𝑡𝑒𝑛𝑐𝑦
Equation 1: Required Capacity Installed
Pmpp - capacity installed (kWp) Wel - energy demand (kWp)
Eglob,sol,panel – local solar irradiance (kWh/m²a) Fpotency – equipment potency
Then, known the PV panel efficiency, it is possible to calculate the PV panel area through the equation (2).
𝐴 = 𝑃𝑚𝑝𝑝
Equation 2: Area of PV Panels .
A – Area (m²)
N - equipment efficiency (%)
Cronemberger et al. (2014) analyzed and compared 35 houses form the Solar Decathlon Europe 2010 and 2012 in terms of: type of integration, architectonic design approach, placement of modules, energy strategy and technical characteristics. Those aspects show up the highlight advances, tendencies and solutions from the SD Europe. Figure 3 summarizes all of his results.
Figure 3: Cronemberger et al. (2014) Study Source: Cronemberger et al. (2014) 50%
50%
Type of Integration
BAPV (Building Applied Photovoltaic) BIPV (Building Integrated Photovoltaic)
36% 28% 24% 12%
Architectonic Design
Approach
Invisible App Highlighted App
Added App Leading App
39% 20% 13% 14% 14%
Energy Strategy
PV modules used only to generate energy
PV modules used also as part of the comfort: thermal, acoustic or lightning conditioning PV modules are hybrid with thermal properties
Tilted and oriented PV modules
Non-optimal tilted and oriented PV modules
47%
25% 16%
12%
Placement of Modules
Sloped Roofs Flat Roofs
Façade Shadding Elements
50% 33%
17%
Technical Characteristics
Monocrystalline silicon cells Multicrystalline silicon cells
F
igure 3 demonstrated that BAPV and BIPV are used with same proportion, the invisible application is the major architectonic design approach, the PV modules is mostly used only to generate energy, the placement of the PV modules is mainly on sloped roofs, and to conclude, the monocrystalline silicon cells has the highest utilization.5.2.3 Hot Water System
Domestic hot water - DHW is one of the main aspect in terms of thermal energy need in a NZEB (MOLDOVAN et al., 2014). Because the solar energy is a clean energy, and it is the richest inexhaustible between all kinds of renewable energy resources, and due to the low cost and easy installation, the solar water heater - SWH is widely used in households (ZHOU et al., 2016). In the table 6, it is possible to see some authors from SD that used this system.
Table 6: Authors that used SWH for DWH in the SD
Source: Private (2016)
A SWH is basically composed by a solar thermal collector, a heat exchange (boiler), a storage tank, pumps, and a system control by valves, temperature and pressure sensors. The figure 4 show a schematic SWH system.
Author System
Peng et al. (2015) BIPV/T
Invidiata & Mizgier (2013) Solar Collectors
Zhang et al. (2014) Solar Thermal Panels
Figure 4: Schematic SHW System Source: Peng et al. (2015)
To dimension a SWH system, it is necessary to calculate the water volume required in order to get the tank capacity. Then, the solar collector dimensions should be calculated concerning its percentage of efficiency, the local radiation and the tilt angle (figure 2). Peng et al. (2015) used an inclination angle of 17° with an installation area of 7,6 m², the heat efficiency of 70% and a storage tank capacity of 400L (150L for the home users and 250L for the radiant floor system). To verify the water delivery temperature, he simulated it by the software EnergyPlus considering the annual incoming and outgoing water temperatures (PENG et al., 2015)
5.2.4 Heating Ventilation and Cooling – HVAC System
The HVAC consumes the largest amount of energy use in a residential building (HOMOD; SAHARI; ALMURIB, 2014). The system is responsible for the 50-70% of the total energy consumption, also, it directly affects the indoor air quality and the indoor comfort (PENG et al., 2015). Common efficient systems available in the market actually are the gas-boilers and the multi-split air conditioners (ADHIKARI et
al., 2012). However, many authors designed their own HVAC systems according to
the house peculiarities. In this case, two macro aspects are considered: the house compositions and the coordination (HOMOD; SAHARI; ALMURIB, 2014).
For SD competition the HVAC systems are widely different from each house. Some strategies are showed in table 7.
Table 7: Examples of HVAC Systems Used in the SD
Author HVAC System
Peng et al. (2015)
Variable Refrigerant Volume (VRV), full-heat-recovery type fresh air unit and integrated
ventilation control system
Alemi & Loge (2016)
Under-floor radiant heating and cooling system. This system was 83.3% more energy efficient in cooling mode and 83.8% in heating mode. The
Aggie Sol home reduces heating and cooling loads by 24.5% and 51.4%, respectively
Irulegi et al. (2014)
Five duct heating and cooling model working as heat exchanger. Three to distribute air and two
to remove it. Also, it had ventilation system.
Shrestha & Mulepati, (2016)
A ductless mini-split heating (10,900 Btu) and cooling system (9,000 Btu), also a
radiant-floor heating system, and a Panasonic FV04VE1 Energy Recovery Ventilator (ERV)
Source: Private (2016)
As showed in the table, there are many HVAC high efficient systems that can be designed to a proposed home, considering the cooling load and heating load calculated trough house compositions and coordination (ALEMI; LOGE, 2016), it is possible to design the one most efficient.
5.2.5 Lightning
The lightning is responsible for approximately 15% of energy consumption in residential buildings (CHOI, H. et al., 2016). Reducing energy use for lightning in a house can be achieved by using integration with daylighting, using low consumption luminaries and light control, and also, using new light sources (CHOI, H. et al., 2016).
Daylighting is a passive strategy (RODRIGUEZ-UBINAS et al., 2014), which can be well performed by openings optimum size calculations (PERSSON; ROOS; WALL, 2006). In addition, PV panels can also be used as comfort strategy to the building lightning conditions (CRONEMBERGER et al., 2014).
Low consumption luminaries presents the LED lighting as the state-of-the-art light source (CHOI, H. et al., 2016), because it has low energy consumption and low heat emission compared with others lightning technologies available in the market (INVIDIATA; MIZGIER, 2013).
The occupancy sensors are a very cost-effective possibility to reduce energy use for lightning (NORBERT LECHNER, 2014). Also, there is the light sensors which is an efficient control method to maintain a required level of illuminance in the local (CHOI, H. et al., 2016).
5.2.6 Appliances and Electronics
The appliances are the third system in energy use demand in a home (INVIDIATA; MIZGIER, 2013). In addition, it affects directly the internal heat gain estimated at 4W/m² (ASFOUR; ALSHAWAF, 2015). The requirement for appliances used in a NZEB, is that all equipment should be high energy star rated (energy efficient) appliances (BERRY et al., 2014). Kwan & Guan (2015) made a sensitivity analysis on high star energy appliances, and he concludes that the energy use can be reduced by 42%, and also, it reduces the heat load which led to 7.5% decrease in the HVAC energy used. The majority articles from SD houses that described their house appliances, said they were all high energy star rated. For example, the electronic and domestic appliances used in the Brazilian house named Ekó House for the SD Europe 2012, they were all classified as low energy consumption (INVIDIATA; MIZGIER, 2013).
The electronics, due to the increase in the number of devices per household, consumes 56% more of energy use than 15 years ago (SHRESTHA; MULEPATI, 2016) . In the same way of the appliances, the electronics of a NZEB should be high energy star rated (BERRY et al., 2014).
5.2.7 Commuting
The cars and the two-wheelers are responsible to the majority of total emissions (60% to 90%) produced by all modes of transport (GROUN, 2013). The
electric vehicles - EV came with intention to benefit energy security, global and local environment and economic growth (DAINA; SIVAKUMAR; POLAK, 2017). Energy security is potentially improved by battery electric vehicles and plug-in hybrid vehicles, that reduce the oil consumption and can be charged by renewable energy sources; global and local climate, and air pollution can be reduced because of the emissions reduction; and economic growth can be stimulated by the EV development and the charging structure development, and also, by a growth of business to operate it (DAINA; SIVAKUMAR; POLAK, 2017). Further, the electric energy stored in an EV battery can be transmitted back to the house power grid, if it is favorable to the peak power balance (ZHOU et al., 2016). To apply commuting in a house, it should be considerate the household daily activity-travel schedules or daily mileage and the EV charges demand, concerning the best EV for the household necessities (DAINA; SIVAKUMAR; POLAK, 2017).
5.3 SOFTWARES
5.3.1 AltoQiThe AltoQi is a software package for small buildings up to 1500m² projects. It is useful for engineers, students and designers of residential and commercial buildings. The AltoQi is composed by the Lumine V4, Hydros V4 and Eberick V4. The Lumine V4 is a software for electric design, it is possible to draw the lamps, the lights switch, the plug-ins and the distribution board; in addition, it allows to calculate the project characteristics, such as electric wire, circuit breakers and AC current. The Hydros V4 permits to design the water plan, it is possible to draw the whole water system, from the water tank to the points of use, also, it allows to dimension the pipes and to verify the pressure. The Eberick V4 is a software feasible to concrete design, which includes the draws, analysis and final dimensioning of the structure.
5.3.2 AutoCAD
A software from the Autodesk suitable for 2D and 3D engineering and architectural design. The tools allow to draw the details of the site plan, the landscaping interior plan, and to specify all the building dimensions and elevations.
The software DesignBuilder was developed in the United Kingdom being a friendly version of EnergyPlus developed by the United States Department of Energy – US DOE. The software is suitable for architects, engineers and energy professionals to simulate the energy performance of the building according to the construction techniques and strategies used. Those tools allow to characterize the building layout, activity, construction, openings, lightning, and HVAC aspects. Also, the software has a heating and cooling design, and the daylighting tools, which allows to evaluate different systems, in order to choose the most efficient one. In addition, the DesignBuilder has the simulation tool, which is responsible for all energy demand calculation based on the whole home model system. The software can also calculate the Window to Wall to Ratio - WWR, and the energy production from the renewable energy sources installed on site. Because of the widely options to model a home which consequently guarantee a great accuracy simulation, the DesignBuilder is suitable to this SD project.
5.3.4 SketchUp
It is a design software useful from the earliest stages of design to the end of the construction. The software has a friendly interface, which it is possible to program, diagram, design, develop, detail and document. The tools allow to produce scaled accurate drawings, generate presentation documents, create compelling walkthroughs, create accurate highly-detailed models, and think by drawing in 3D. It also, can import AutoCAD 2D files and created the 3D version to show realistic pictures of the project.
6 METHODOLOGY
This research aims to design a house based on the Solar Decathlon Competition. The house is going to be designed using software such as SketchUp, AutoCAD, Lumine V4 and Hydros V4 and optimized by DesignBuilder simulation considering all the evaluation aspects of the contests cited before. Also, the rules and the requirements of the competition will be obeyed. The choices made can be encouraged by the state-of-art, highlight strategies, innovations, and solutions applied into the main strategies. The local site will be considered Cuiabá MT - Brazil. To develop this house, this work is going to be separated in two phases as showed in figure 5 and figure 6.
Figure 5: Flowchart Phase One Source: Private (2016)
Phase One
Project
Architectural
Engineering
Water
Appliances
Figure 6: Flowchart Phase Two Source: Private(2016)
6.1 PHASE ONE
The first phase aims to develop the home project, choosing and planning all the systems and the elements of the building.
6.1.1 Architectural
According to the Decathlon & Rules (2016), it will be designed a house with the finished square footage between 600 ft² and 1000 ft² (55 m² and 93 m²), the constructed footprint less than 2700 ft² (250 m²). and the ceiling height with at least 7ft (2 m) of headroom. The house will present kitchen, bedroom, restroom, washroom and TV room. The project will detail a site plan with: footing locations, plantings, containers, deck and additional site elements; and a landscaping interior plan including the dimensioned floorplans, furniture layout and cabinetry. All the building dimensions have to be presented, such as wall, floor and roof sections. In addition, the reflected ceiling plan, roof plan and elevations has to be determined. Further, the passive strategies to increase energy efficiency will be planned such as cross ventilation, natural and artificial lightning integration, etc. For this step, it will be
Phase Two
DesignBuilder
Simulation
Health and
Comfort
Energy
Analysis
Result
Energy
Balance
Market
Potential
Home Final
Score
used the programs AutoCAD and SketchUp to create a coherent and comprehensive draws.
6.1.2 Engineering
For the house engineering, it will be dimensioned the temporary foundations and anchors considering the ground anchorage; the stake capacity it will be assumed as: 1250 pounds vertical withdrawal (567 kg); and 1500 pounds horizontal shear (680 kg), in agreement to Palatine (ILL.) (1976). Then, it will be necessary to project the structural system, it will be determined the wall and frame compositions and the dimensions of the system able to support wind of 85mph (136 km/h), exposure category C; IRC Seismic Design Category (SDC) D; railings of 200lb (90 kg); live load for interior floor, decks and ramps of 50psf (244 kg/m²), and exteriors of 100psf (488 kg/m²); roof live load of 20psf (97 kg/m²), and temporary paved surface of 6,000psf (29300 kg/m²), according to the Palatine (ILL.) (1976). The calculations will be done by hand.
The building envelope will be designed using simulation according to Yun et
al. (2010). It will be tested different envelope systems with different passive
strategies (table 6), in order to get the most efficient model for the solar gains, heat loss and daylight desirable. The simulation will be done by using the DesignBuilder software.
For the electrical system will be used the PV system as a renewable energy source, considering the fact of it is the best technique to convert solar energy into electricity (ZHOU et al., 2016). According to Decathlon & Rules (2016), it will be specify the Direct Current – DC electrical plan and the Alternating Current – AC electrical plan. The DC electrical plan includes the PV system composed by PV panel, a PV inverter, the distribution board and the storage battery as illustrated in figure 1. Following Zhang et al. (2014), it will be first calculated the total energy demand from the home. For the electronics and for the appliances, as Invidiata & Mizgier (2013) did, it will be created a schedule with equipment, power (W), and time of use/day (h), in order to calculate the heat load and the energy demand from them. Then, using the software DesignBuilder it will be identified the most suitable tilt angle of the PV panel. With the solar irradiance, the energy demand and the PV panel power, the next step is to calculate the required capacity by the equation 1, and later, the PV panel area by the equation 2. The AC plan, includes to draw all the electric
plug-in in home space and also to characterize the board distribution and the storage battery. For this step, is going to be used the program Lumine V4 from AltoQi. Beyond, in agreement with Cronemberger et al. (2014), and its analysis on highlight advances, tendencies and solutions from the SD Europe. It will be used the invisible application for the architectonic design approach, the PV modules will be used only to generate energy, the placement of the PV modules will be on sloped roofs, and to conclude, the monocrystalline silicon cells will be adopted.
For the HVAC system, according to Homod; Sahari; Almurib (2014), it will be designed considering two macro aspects: the house compositions and the coordinates. Those aspects will allow to calculate trough DesignBuilder the cooling load and the heating load to perform thermal comfort requirements cited before. Alemi & Loge (2016) calculated the heating and cooling load, and then it was chosen the HVAC system with the most satisfactory energy efficiency. In the same way, for this project, the HVAC system is going to be designed according to the cooling and heating load, comparing the energy savings from different systems through the DesignBuilder software.
For lightning comfort, it will be used strategies such as daylighting integration, low consumption luminaries and light control, according to CHOI, H. et al. (2016). Daylighting integration will be achieved by optimum openings size (PERSSON; ROOS; WALL, 2006). Low consumption luminaries will use all lamps to be LED, because it is the most energy efficient available in the market (INVIDIATA; MIZGIER, 2013). In addition, light control or occupancy sensors will be simulated, in order to analyze the cost-effectiveness of them. In case of lightning control is chosen it will be set the 300lux level of illuminance required, in agreement to the Decathlon & Rules (2016).
6.1.3 Water
According to Decathlon & Rules (2016), the house should be able to deliver 15 gal of hot water (57 l), with temperature equal or above 110°F (43°C). To match the competition requirements, the water system will be designed in agreement with Peng
et al. (2015). The thank water will have capacity of 150L, and considering the solar
collector efficiency as 70% and the local radiation of Cuiabá, it will be simulated by the software DesignBuilder the better tilt angle (figure 2), and the necessary area of installation for the solar collector. The DesignBuilder will be used also, to verify the
water delivery temperature, in order to determine if the SWH system is satisfactory to the SD requirements.
Further, in this step it will be specified the plumbing plan and isometric plan, including water delivery points, water storage tank, water reuse system, and solar thermal panels, in agreement with Decathlon & Rules (2016) requirements of water drawings. The program HydrosV4 will be used to this task.
6.1.4 Appliances
The house appliances will be chosen in this stage. They are: a freezer, a refrigerator, a washing machine, and a clothes dryer. According to Berry et al. (2014), all the equipment chosen will be high energy star rated available in the market. This choice is in favor of get a lower energy consumption and a lower heat load (KWAN; GUAN, 2015). In addition, they will be chosen in agreement with Decathlon & Rules (2016) requirements - the refrigerator shall be a minimum volume of 4.5ft³ (1.3 m³), and the freezer volume shall be a minimum of 2 ft³ (0.05 m³).
6.1.5 Home Life
This step it is going to be defined the home electronics and the commuting. The home electronics (television and computer), in the same way of the appliances, it will be chosen high energy star rated available in the market (BERRY et al., 2014). This choice is concerning a lower energy consumption and a lower heat load (KWAN; GUAN, 2015). At last, the Decathlon & Rules (2016) will be considerate, which requires a television with minimum display of 27 in (68.6 cm), and a computer with a minimum display of 15 in (38 cm).
For the commuting, according to Daina; Sivakumar; Polak (2017), it will be chosen an electric vehicle considering its battery demand and household millage necessity. On the Decathlon & Rules (2016) condition, the EV should drive at least 25 miles (40 km), in no more than 75 minutes. The EV has to be charged from the house electric system, and its battery must be full at the end of completion task. In this way, an EV available in the market will be chosen in order to match the competition requirements.
In this phase will be simulated the health and comfort of the home, in order to calculate the energy demand by all systems to satisfy the requirements of the contest cited before. Then, it is going to be analyzed the energy balance of the house and the market potential. Lastly, it will be scored the total points of the house according to Decathlon & Rules (2016).
6.2.1 Health and Comfort Simulation
All criteria for health and comfort contest will be simulated by the software DesignBuilder. To simulate those aspects, it will be necessary to model the house in the software interface as much detailed as possible. The input data includes all the house details: layout, activity, construction, openings, lightning, and HVAC system. The more specified the details are, the more reliable is going to be the results. Concerning Decathlon & Rules (2016), the temperature (68°F to 74°F / 20°C to 23°C), humidity (35% to 60%), indoor air quality (CO2 level below 1000 PPM / 998.85
mg/l), air tightness (less or equal to 0.05 CFM 50/ft²), and lighting (300lux or greater) will be judged as acceptable or not. If necessary, some details of the house determined previously in the architecture and in the engineering stage can be changed, in order to get the most satisfactory house model.
6.2.2 Energy Simulation
Using also DesignBuilder software, in this phase is going to be calculated the energy consumption of the house in kWh. The software considers the energy demand from the HVAC systems, the appliances, the electronics, the lightning and the electric vehicle in order to add a final energy demand amount of the house. In this phase, some changes can be done too, concerning the most efficient energy performance of the building.
6.2.3 Energy Balance Analysis
For this step, it will be compared the energy production (kWh) from the PV panels installed in the house and defined in the engineering stage, with the energy demand (kWh) calculated in the energy simulation. According to Decathlon & Rules (2016), the house energy balance most satisfactory is the one with zero balance. So, the objective in this step is to classify the results from the energy balance as satisfactory or non-satisfactory.
6.2.4 Market Potential Analysis
Knowing the construction budget ranges from $250,000 (R$100000) to $600,00 (R$180000), according to the Decathlon & Rules (2016), the house budget will be calculated by the Sinapi excel spreadsheets, including materials price and labor cost. If the money amount is equal or less than the required range, then the house is going to be classified as a market potential one. Moreover, it will be calculated the home composite payback, in others words, it will be calculated the time necessary for the economy in electricity be equal to the invest on the house renewable energy system. Furthermore, it will be also calculated the Liquid Present Value – LPV, in order to classify the house as profitable or not.
6.2.5 Home Final Score
Considering that some contents are scored by jury, it will be count into this work only the qualitative scores. They are: engineering, market potential, water, health and comfort, appliances, home life, and energy. So, the range for the home score is from 0 to 800 points. At the end, the scores by contest will be compared with the scores contest from the Solar Decathlon 2017 houses, in order to get a ranking to the home designed in this research.
7 EXPECTED RESULTS
At the end of this work, it is expected to achieve the following results: Designing a NZEB with attractive design and low cost budget; Getting a satisfactory final score;
Demonstrating the benefits of building energy-efficient homes; Showing the accessibility of this type of construction;
Educating and qualifying academic students involved in the work,
Informing and raising public awareness for the importance of sustainable construction.
8 SCHEDULE
ACTIVITIES
YEAR 2017/2018
APR MAY JUN JUL AUG SEP OCT NOV DEC JAN
Architecture
Engineering
Water
Appliances and Home Life
Heath and Comfort Simulation Energy Simulation Energy Balance Analyzes Market Potential Analyzes Article Write Article Review Results Presentation
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