54549 FLEX HOUSE ES2011-54

Proceedings of ASME 2011 5th International Conference on Energy Sustainability & 9th Fuel Cell Science, Engineering and Technology Conference

ESFuelCell2011 August 7-10, 2011, Washington, DC, USA

54549

FLEX HOUSE

Stanley Russell University of South Florida

Tampa Florida, USA

Mark Weston University of South Florida

Tampa Florida, USA

Yogi Goswami University of South Florida

Tampa Florida, USA

Matthew Doll University of South Florida

Tampa Florida, USA

ABSTRACT Flex House is a flexible, modular, pre-fabricated zero

energy building that can be mass produced and adapted easily to a variety of site conditions and plan configurations. The key factor shaping the design is central Florida’s hot humid climate and intense solar radiation. Flex house combines the wisdom of vernacular Florida houses with state of the art Zero Energy House technologies (ZEH.) A combined system of photovoltaic panels and solar thermal concentrating panels take advantage of the region’s abundant insolation in providing clean renewable energy for the house. Conservation is achieved with state of the art mechanical systems and innovative liquid desiccant dehumidification technology along with highly efficient lighting and appliances. The hybrid nature of the Flex house allows for both an open and closed system to take advantage of the seasonal temperature variation. Central Florida buildings can conserve energy by allowing natural ventilation to take advantage of passive cooling in the mild months of the year and use a closed system to utilize mechanical cooling when temperatures are too high for passive cooling strategies. The building envelope works equally well throughout the year combining an optimum level of insulation, resistance to air infiltration, transparency for daylight, and flexibility that allows for opening and closing of the house. Flex House is designed with a strong connection between interior spaces and the outdoors with carefully placed fenestration and a movable wall system which enables the house to transform in response to the temperature variations throughout the year. The house also addresses the massive heat gain that occurs through the roof, which can generate temperatures in excess of 140 degrees. Flex House incorporates a parasol-like outer structure that shades the roof, walls and

FIGURE 1 Northern exposure showing louvered solar umbrella and extended bedroom module.

Proceedings of the ASME 2011 5th International Conference on Energy Sustainability ES2011

August 7-10, 2011, Washington, DC, USA

ES2011-54549

1 Copyright © 2011 by ASME

2 Copyright © 20xx by ASME

courtyard minimizing heat gain through the building envelope. To be implemented on a large scale, ZEH must be affordable for people earning a moderate income. Site built construction is time consuming and wasteful and results in higher costs. Building homes in a controlled environment can reduce material waste, and construction costs while increasing efficiency. Pre-fabricating Flex House minimizes preparation time, waste and safety concerns and maximizes economy, quality control, efficiency and safety during the construction process. This paper is an account of the design and construction of Flex House, a ZEH for central Florida’s hot humid climate.

INTRODUCTION

Architects and engineers today are charged with building a world where the most insurmountable problem will soon be resource management. Sustainability is riding an unprecedented wave of popular culture, but many of the tools necessary for the job have been laid before us by previous generations; building sustainably is good design, and always has been. However, long before architects began designing for natural lighting, cross ventilation, and solar efficiency, vernacular building typologies evolved out of necessity to address human comfort with the genius loci wrought from local materials, local labor, and knowledge passed down through generations. From these humble beginnings come the basic tenets of sustainable design: daylighting, passive ventilation, passive solar design, and water collection. FLeX house uses these concepts as a point of departure, augmented by active technologies for the generation of power, efficient heating and cooling of air, and to assure indoor air quality. At the core of this philosophy is the rejection of the ornamentation of normative building modes with sustainable “elements” in favor of site specific architectural intervention and building performance. FLeX is a house for Florida.

1.1 PASSIVE STRATEGIES IN VERNACULAR ARCHITECTURE

From the early 1800s white settlers began to trickle down from the northern states and establish homesteads in the Florida wilderness. Their houses became known as cracker houses. Like most homesteaders at the time, the Crackers built walls by stacking pine logs on top of each other with notched ends that interlock with adjoining walls at the corners. Although the same type of dwelling was built across the country, the Cracker house had features that were unique adaptations to the hot, humid Florida climate. While in cold climates it was often much easier to place the logs directly on the ground or on a layer of foundation stones, the cracker house logs were raised on piers to protect the wood from rotting on Florida’s moist, warm ground. In cold climates the floor was often made of earth but in Florida, where air movement is essential to thermal comfort and the longevity of building materials, the floor was framed in wood and raised off of the ground so that air could circulate under the building. Whereas the northern settler’s

dwellings had little or no roof overhang, the cracker house typically had a wide covered porch on one, two or three sides that shaded the building from the hot sun and provided a covered, exterior space for work or leisure. [2]

Cracker houses were built of wood and metal, materials with low thermal mass that are well suited to the Florida climate. Given that the Crackers were adapted to Florida’s climate and their thermal comfort zone must have been several degrees higher than ours is today, one can imagine that the Cracker house with its wide shady porches provided them with a reasonably comfortable living environment. Meanwhile, the architectural style of choice of the high society people vacationing in Florida in the late 1800’s was not the humble wooden cracker house but the masonry and stucco style of the exotic Spanish Mediterranean. With masonry walls and heavy tile roofs that absorb heat, small windows that inhibit ventilation and minimal roof overhangs that allow the sun to bake the masonry walls, these houses were the antithesis of effective passive solar design in a hot, humid climate. But despite its lack of affinity for the Florida climate, the Mediterranean Revival style [Med-Rev] is favored by many, to this day, for its image of substance and wealth. One important exception to the Med-Rev trend began in the early 1940's when a small handful of idealistic architects brought their brand of modern, regional, functionalism to Florida to redefine Florida vernacular in a way that celebrated the region’s environmental assets while responding to its climatic challenges.

1.2 PASSIVE STRATEGIES IN MODERN ARCHITECTURE

Columbia University educated Ralph Twitchell, a designer and builder, opened his office in Sarasota, Florida in 1936 after spending the early part of his career in New York and France. Twitchell saw Florida as a paradise and sought to design buildings that worked with and accentuated Florida's natural beauty. In the early 1940s Paul Rudolph graduated from Alabama Polytechnic Institute [API] and went to work for Twitchell. While in Alabama, Rudolph had studied the climatic responses of local vernacular architecture and those ideas were fresh in his mind when he arrived in Florida to begin working with Twitchell [1]. The combination of environmental awareness, construction experience, and design savvy of the Twitchell /Rudolph team led quickly to works that brought national attention to Sarasota and the uniquely Florida houses that the team designed. The houses were built in a distinctly modern vocabulary that was also distinctly regional. The deep overhanging eaves, absent in the Med-Rev architecture of the day, were used to shade the building and to make shaded outdoor spaces recalling the cracker house design. Many houses included outdoor rooms enclosed with screens. Large sliding glass panels or louvered windows allowed entire walls to be opened for ventilation and to expand the interior space into the landscape. A variety of shading devices including louvers and screens helped protect the windows and walls from


the hot Florida sun. In many cases the louvers were adjustable to respond to various sun angles or weather conditions such as vertical storm shutters that pivoted up to become horizontal sun shading devices. The plans were often elongated on the east west axis to allow cross ventilation in rooms and maximum shading for walls. The relevance of the Twitchell/Rudolf houses today lies in their skillfully conceived passive responses to the hot humid climate and their open planning and clean modern aesthetics that continue to suit contemporary tastes and lifestyles [3]. As air conditioning became more prevalent in the 1950's however, the necessity for climatically responsive architecture in Florida diminished. With the exception of a brief period of revived interest in the Cracker house, little serious consideration was given to passive solar design and energy efficiency again in Florida until the late 1990s, when the Florida Solar Energy Center [FSEC] began its research on ZEH.

1.3 ZERO ENERGY HOUSE RESEARCH IN FLORIDA In the state of Florida in the 1990s the increasing

affordability of PV technology began to open the door to site based electrical generation which, along with solar thermal technology, takes advantage of the state’s wealth of insolation. In 1998 the Florida Solar Energy Center [FSEC] began its ZEH research program in collaboration with the City of Lakeland municipal utility.

The team constructed a 2400 sq. ft. energy-efficient photovoltaic residence [PVRES] and a standard model [the Control] with the same footprint and tested them both for more than a year. In one year, the PVRES home used 6960 kWh of electricity and had a PV system production of 5180 kWh. For the same year, the control used 22,600 kWh without any PV production. The yearly energy savings due to differences in energy efficiency of the two homes was 70% for the PVRES house. Deducting the PV system's production, the PVRES house's net energy use for the entire year was only 1780 kWh a 92% utility energy savings compared to the standard house.

Perhaps even more important than annual energy use is the fact that during periods of peak electric demand, the PVRES house, due to the PV system, placed nearly zero net demand on the utility system. Both test homes have R-30 fiberglass insulation blown in the attic, but there are major differences in the building envelope and mechanical systems of the two buildings.

The building envelope of the PVRES house features a 77% reflective white concrete tile roof. The control home's roof is made of conventional, 7% reflective gray asphalt shingles. When the outside summer air temperatures were at their peak the coincident peak attic air temperature was 91.4oF in the PVRES compared to 131.50 in the house with gray asphalt shingles. For solar control on walls and windows, the PVRES home has a 3 foot wide overhang around the entire perimeter of the building while the standard home has a one and a half foot roof overhang. The overhang of the PVRES home shades most of the wall and at least 75% of the south and east window area.

In conventional residential construction in Florida, walls are insulated on the interior of the masonry walls exposing the exterior to the hot sun and ambient air temperature and allowing the masonry to store excess heat and pass it slowly to the interior spaces. Conversely, the concrete block walls of the PVRES home were covered with R-10 insulation on the exterior to keep the masonry from absorbing excess heat from the outside.

The mechanical systems of the two buildings also had marked differences. In conventional Florida house construction the ducts and often the air-handler are located in an un-insulated attic space. In Florida, the attic sometimes reaches 130o F and studies show that heat transfer to the duct system can reduce the cooling capacity of the air conditioner by 30%. In the PVRES house the air handler and ductwork are placed within the conditioned space of the building. The PVRES home uses a solar water heating system with propane back up. The system consists of a forty square foot solar collector mounted on the south side of the home's roof. The control home contains a standard electric resistance 52 gallon storage tank in the garage rated to use 4,828kWh/year.

The PV generation system for the PVRES was sized to provide power that would offset most of the daytime household electrical loads. Based on the predicted loads for a peak day, it was determined that a 4kW solar array should be installed [4].

The Lakeland project and several other research projects in the past 12 years have shown that a well-designed building envelope, energy efficient mechanical systems and appliances and a solar array for electric generation and hot water production, can be combined to produce affordable houses that achieve near net zero or net zero energy consumption in Florida. Team Florida took the lessons derived from research and vernacular and modern precedents as a starting point for the design of Flex House.

To verify the effectiveness of our solar shading strategy, we constructed 3- 8’x8’x8’ cubes, each having a different type of skin to measure how the different skin configurations

FIGURE 2 Solar Shading test cube at work.


affected heat gain inside the modules. The experiment was based on the hypothesis that even with well insulated roof and walls shading and ventilating the exterior skin of the building would significantly reduce heat gain in the modules. All three of the modules were built out of r-16 structural insulated panels with an aluminum skin and 4” expanded polystyrene core. The control module had no additional skin treatment over the SIP. The second module had a ventilated skin on the top, south, east and west sides made by using ¾” wood strips to fur out plywood from the surface of the SIPs. The third module had a louver structure covering the top, south, east and west sides. There was a 4” space between the louvers and the surface of the SIPs.

All of the modules were equipped with doors so that they could be completely sealed off during the testing period. A heat sensor was hung from the ceiling on the inside of each module and the modules were set in the sun from 9am until 7pm on a sunny day in June. The heat sensors sent data back to a data logger attached to a PC and the results were stored and graphed. At 5:30 pm when the modules reached their peak temperature the module with the shading louvers was a full 7 degrees cooler than the control module and about 3 degrees cooler than the module with the ventilated skin. The test confirmed our hypothesis that shade is a crucial element to reducing heat gain and creating thermal comfort in Florida buildings. We also learned that the type of skin and dimension of the ventilated space between the outer and inner layers has an impact on heat gain.

2.1 FLEX HOUSE The FLeX House is a flexible, modular building system

that can adapt easily to different site situations and plan configurations. The dwelling is designed for a young couple living in Central Florida on a moderate income. The key factor shaping the design approach is central Florida’s hot humid climate and intense solar radiation.

Designing an envelope that works equally well throughout the year combining an optimum level of insulation for temperature extremes, resistance to air infiltration, transparency for daylight, and flexibility, is a challenge in central Florida. The FLeX building envelope combines prefabricated stick built construction, batt insulation, and plywood sheathing with inexpensive corrugated galvanized siding hung in a rain-screen fashion. The result hybridizes vernacular material aesthetics with standardized construction techniques to produce an enclosure that best balances efficiency, sustainability and economics. The galvanized finish is an extremely durable solution for both inland and coastal locales.

The flexibility inherent to the architectural design of the house, which allows it to take on different configurations by operating movable elements that expand or contract the living spaces for transport or user preference, is supported by the continuity of interior materials applied to flooring, ceilings, and interior walls. Flooring and all wooden finishes are made exclusively from sustainably harvested Florida Cypress which is both weather and insect resistant without chemical treatment.

FIGURE 3 Heat Gain Test Results. Black line: control module, a bare SIP with aluminum skin. Blue line: SIP module with ventilated skin. Green Line: SIP module with a louvered shading device [FIGURE 2]. The graph shows that around 5:30 pm at the peak temperature the control module temperature was about 113 and the louvered module was about 106.


Material changes in the foyer respond to the nature of these moisture-prone or transitional areas, whereas consistent materials echoing outdoor components in the built-in casework throughout the house visually integrate all indoor and outdoor spaces by providing a visual continuity from the cypress plank floor to the exterior cypress decking. All interior and exterior finishes in the FLeX House carry on our objective to build with green materials that ensure optimal insulation, thermal capacity reflectivity balance, and low emission of volatile organic compounds. Selection criteria emphasize appropriateness of use and aesthetic value while considering durability and ease of maintenance, as well as green attributes such as recycled content and recyclability, embodied energy and energy efficiency, and health impacts.

The FLeX House engineering approach combines conservation measures with cutting edge technologies in a system uniquely suited to the central Florida climate. Team Florida has used energy simulation software, as well as monitored case studies to “right size” the building and mechanical, electrical and plumbing systems. The Florida State University Off-Grid Zero Emissions Building [OGZEB] was used as a full scale testing lab for technologies integrated into the The FLeX House. The FLeX House uses a combined system of photovoltaic panels with micro-inverters for the generation of electricity, and solar thermal panels for the generation of hot water.

To keep energy consumption to a minimum, efficient appliances are essential. The FLeX House will include smart grid appliances that communicate to prevent multiple high draw appliances from operating simultaneously, reducing spikes in demand on the grid. Lighting is a major consumer of energy in buildings. FLeX House uses maximum daylight penetration to significantly reduce energy costs by negating the need for excessive electric lighting, consequently reducing heat and air conditioning loads. At night LED and fluorescent lights provide energy efficient illumination.

The FLeX House makes the best use of natural day light for its interior spaces with large glazed areas on the north and south facades. The building envelope itself is a narrow rectangular, 1,000 square-foot enclosure oriented with its long axis east-west to reduce problematic sunlight exposure at the narrow ends. A louvered cypress shading umbrella wraps the building in order to control the amount of direct sunlight that hits the glazing system, reducing heat gain through windows and doors. The umbrella incorporates active solar technology at the roof of the building, and uses these elements to provide shading for the roof, as well as to provide ample air space for ventilation of heat buildup at that level. Perhaps most importantly, the solar umbrella also serves to create the ample shaded outdoor spaces which are an essential component to life in the southern American states.

2.2 STRATEGIES FOR MECHANICAL SYSTEMS The envelope of the FLeX house is extremely well sealed

against leakage in order to ensure maximum efficiency in its mechanical systems. Fresh air exchange, however, is necessary in order to promote maximum indoor air quality. To this end, Mechanical systems incorporate an energy recovery ventilator, or ERV. The ERV serves to assist mechanical systems in winter by exchanging heat and humidity from stale indoor air into the incoming outdoor area. In summer, this process is reversed, delivering cool dry, fresh air to the interior.

In hot and humid regions, such as Florida, where the relative humidity is high, the latent load becomes a big problem. Properly sized conventional vapor compression systems sometimes cannot even meet this load. Consequently, oversized compressors are installed to dehumidify the incoming air. To meet humidity requirements, vapor-compression systems are often operated for long cycles and at low temperatures, which reduce their efficiencies and require reheating the dry, cold air to achieve comfort conditions. Both consequences are costly. However, a combination of a

FIGURE 4 Southern exposure showing drop‐down shade component, verticaleast facing louvers of the solar umbrella, shaded exterior porch, andfully extended entryway.


desiccant dehumidification system and a vapor compression system (also known as hybrid desiccant cooling system) will not only meet the load but also save energy. A detailed review of liquid desiccant cooling system was given by Oberg and Goswami [5].

Commercially available desiccants include silica gel, activated alumina, natural and synthetic zeolites, titanium silicate, lithium chloride, calcium chloride, triethylene glycol and synthetic polymers. In an earlier study by Mago and Goswami [6], an aqueous solution of lithium chloride was used as the desiccant in a test house at the University of Florida. Fumo and Goswami [7] had earlier studied the heat and mass transfer performance for this desiccant for air dehumidification. These studies showed that liquid desiccants like lithium chloride and calcium chloride can be very effective in hot and humid climates. Therefore, calcium chloride solution was chosen as the liquid desiccant for the FLeX house in a design that is both functional and attractive.

FLeX house uses an innovative Liquid Desiccant Waterfall to absorb water directly from the air entering the building. As the liquid desiccant absorbs water, the solution of calcium chloride and water becomes more dilute and must be recharged. To do this, the liquid is heated, allowing water to evaporate to the exterior. Once re-concentrated, the solution is then returned to the waterfall. For demonstration purposes, and to showcase the beauty of the technology, the waterfall is made a visible interior feature, fabricated as a Plexiglas waterfall tube through which the liquid can be seen flowing from the main space of the house.

2.3 VERNACULAR BONES, TECH MUSCLE Today, computers can be found in items we use everyday

like our cars, coffee makers and toys but we have yet to truly integrate them into our homes and workplaces. While other industries have embraced the incorporation of technology into

their products, the American home lags behind. Even the cars we drive are infinitely smarter than our houses, with the ability to monitor energy usage, maintenance schedules, and to automate headlights and door locks [8]. Currently available home automation systems are expensive, rely on a centralized computer, and are inherently unreliable. FLeX House tackles these hurdles with an approach to home automation which is robust, affordable, and performance based to create a truly “Smart” home from the ground up.

The key to the FLeX approach relies on the use of commonly available and inexpensive microcontrollers to create a system of wired and wireless sensor nodes which can easily be integrated throughout the home, creating a distributed device network which permeates the building. This system can consolidate existing control systems, security systems and thermostat controls into a single unified mesh that creates a foundation for a new generation of integrated devices. Inputs such as light switches and security sensors use software links to outputs rather than hard wiring to actuate lights, shades, locks and mechanical systems.

Our custom software environment, devised by a USF student, is called HomeNet, and is comprised of prebuilt open source hardware and software modules. Built on the open-source projects Arduino (http://arduino.cc) and Processing (http://processing.org) under a GNU GPLv2 and GNU LGPL license, HomeNet simplifies the programming and setup of device nodes so that anyone can easily build and access their own network, regardless of their skill with a computer. HomeNet is a flexible environment accessed via Internet, Email, Facebook and Twitter as a means to control devices remotely or to set up automated routines. Energy usage reports are automatically compiled and are organized by room, appliance, or even by power outlet, helping to eliminate energy waste at many scales. With HomeNet, almost anything can be connected to a sensor node for monitoring and remote control, including but not limited to: temperature, humidity, power, occupancy schedules, and window operation incidences.

The HomeNet protocol is a simple messaging system for sharing information over a variety of transport methods. The HomeNet Protocol uses light weight packets with an 8 byte header and a 2 byte checksum which is just a fraction the length of other protocols like TCP/IPv4. This balances features with overhead and still supports the ability for different versions, packet types, priorities and encryption. It was inspired by the packets of Internet‐0 [9]. HomeNet Breaks away from the need to have direct compatibility with IPv4, allowing for even smaller packets. The node address is reduced in length from 32 bits to 12 bits to save memory but also reduces the number of nodes in a network from billions to a maximum of 4096, a number largely sufficient for most homes. Most nodes will be behind a gateway or firewall and do not need direct access to the Internet.

FIGURE 5 Section through FLeX showing solar panels above, space betweenthe building envelope and the louvered solar umbrella, and revealingstick frame construction.


Size Packet Format

8 bits Packet Length

2 bits Version

2 bits Packet Type

1 bit Reply/ACK

1 bit Encrypted

1 bit 0:Automatic/1:Manual

1 bit Priority

12 bits From Node

4 bits From Device

12 bits To Node/TTL

4 bits To Device

8 bits Packet ID

8 bits Reply/ACK ID (only with flag)

8 bits Encrypted Payload Length (only with Encrypt Flag)

8 bits Command/Payload Type

≥ 48 bytes Payload

16 bits CRC16 Checksum

Nodes provide the brains for the devices and link them into HomeNet. They translate HomeNet commands into actions for the devices, read data from the devices and send the data to other nodes and devices. In HomeNet, these nodes are based on JeeNode (http://jeelabs.org) boards, an affordable Arduino derivative that also incorporates a low cost wireless transmitter. Future nodes could be based on ARM, PIC or other microcontrollers. Nodes can be broken out into 4 types based on their roles: Device Nodes, Network Nodes and Public Nodes, and Master Nodes. Depending on a nodes configuration, it might have multiple roles.

Device Nodes are remote nodes around the home that gather data from sensors or control actuators connected to them. They connect wired or wirelessly to a Master Node that tracks and collects the nodes' data. Future versions of HomeNet could implement a mesh network to build a more robust network.

Network Nodes translate packets between different transport methods. For example, from a wireless network to a wired and back. These nodes may also have the capability to store packets in the case of a connection failure. A network node links your HomeNet network to your PC via USB.

Public Nodes are nodes directly connected to the Internet. These could be in the form of an App running on your PC or it could be a node with a built in Ethernet card. It provides a link for HomeNet Device Nodes to send data to the cloud to be stored and archived. The current Public Node was written in Processing (Java) and can be run on a netbook.

The Master Node tracks and monitors the health of nodes and stores the collected sensor data and schedules for devices that have been programmed. In the prototype, the master node runs on the HomeNet.me website, but in the future, the task of

the master node could be running on hardware inside of the home.

HomeNet can interface with practically any device in the home. Devices can be any smart object, or sensors and actuators that you wish to integrate into HomeNet. They can be inputs like temperature and humidity sensors or outputs like lights, window blinds, and your air conditioner.

Control devices vary from being very simple switch to your cell phone running an app that can control and interact with every device in the home. Simple controls such as Light Switch, Door bell, Button panels are no longer hardwired to devices, rather they are programmed to meet your needs and can be reprogrammed if your needs change. You can control one device or one hundred devices and could change based on the time of day or what is going on the home Multifunction Panels such as Thermostats, Security Panels, Sprinkler System Controllers, and Pool Timers have typically been self contained devices that had their own user interfaces. In a smart house these devices break free of their housing and join a larger network so you can program these devices from more user friendly devices like your laptop or cell phone. Portable devices such as Cell phones and Tablet PCs can interact with any devices in the home and can act as a universal remote control. These controllers connect directly to the master node to access all of the devices in the network. A PC is the ultimate controller in the system. Not only can you view and interact with the whole system, you can reprogram the hardware and change how the system works.

Homenet provides alerts so that the user may quickly understand what is happening within the network. Information from an array of sensors is actively tallied and processed. Users can be quickly alerted via text message, email, or post to social media sites like Facebook and Twitter to events within the network. A Check House Light serves as a visual reminder to check on your house and can alert you to for maintenance, bad air quality and broken devices. In case of an emergency, like a fire, audio alarms can sound through the house. Digital Photo frames, and Weather displays are becoming increasing common in the home. Such small screen devices can be made to also display real time information about the home. Information about can also be overlaid on a television screen

TABLE 1 HomeNet Packet sizes. See ANNEX A for format descriptions.

FIGURE 6 HomeNet Nodes and Hardware. See www.homenet.me for a complete listing.



showing data such as video from the front door when the door bell rings. Ambient Information devices provide information through color that can be casually observed. For example, it could change from yellow to blue to indicate the current weather or glow green to red depending on current energy use. A trial in Canada of a similar device that showed energy use, lead to an average 6.5% energy savings [10].

Wiring in the home is simplified. Devices no longer have to be hard wired together, lights no longer have to be wired directly to a wall switch for control and it reduces the amount of expensive copper wiring required. Sensors can be embedded deep into the structure so that the system can monitor for things like structural instability, moisture intrusion, insect infestation, and leaking pipes. In new construction, it is preferred to use a simple wired network rather than go wireless so you don't have to worry about replacing batteries , interference with neighbors and provides better security against outside intrusions and snooping. Any additional installation and setup costs can be minimized by using prefabricated construction. Sensors and actuators can be integrated directly into components like doors and windows in the factory rather than during construction on the job site. Nodes and sensors can be installed and setup inside the factory and are ready to start working as soon as the building is assembled. Designers should keep in mind that the system will require maintenance and some component may need to replaced over time. Nodes and devices should be installed where they can be accessed in the future if needed, especially until the technology is proven. Motorized actuators are likely to wear out over time and sensors might break and fail, especially those exposed to the elements. Designers should be conscious of the systems needs and place them where they won't need any additional access covers like installing them behind planned electrical outlets and light switches.

The HomeNet platform is available for free, under a GPLv3 license at www.HomeNet.me.

2.4 LANDSCAPE AND WELLNESS The FLeX house embraces architectural excellence and

sustainable design, as a socially equitable enterprise, an essential component of healing and wellness [11], and as a unifier for a dynamic coexistence of healthy activities. As a flagship for sustainable design and wellness on campus, the FLeX is designed to maximize natural cross ventilation, natural lighting, and will be constructed with materials containing minimal amounts of volatile organic compounds to create a healthy interior environment. An energy recovery ventilator will circulate fresh air through the house minimizing the build-up of CO2 and other allergens and poisons.

The building is designed to promote a healthy indoor/outdoor lifestyle with an entire north wall of sliding glass doors that open up to combine the interior space and garden into one continuous living environment. The garden is a unifying green space which addresses an observed correlation between wellness and exposure to nature. Whenever possible sustainable landscaping practices will act to preserve or

remediate the natural environment of Florida. Grey water recycling and rain water collection will be used to ensure minimal impact on the local watershed.

This unifying green will be associated within the pedestrian circulation of the campus of University of South Florida in order to promote walking, bicycling and other healthy activities. The goal of this healing garden is to create a beautiful, safe, and low-stress environment for contemplation, rest, light exercise, gardening and educational activities. Care will be taken, however, to ensure an enabling and safe setting for its users and its programmatic usages for persons of all abilities; universal design lies at the core of the FLeX philosophy.

3.1 FUTURE To be deployed on a significant scale, cost-effective,

energy and efficient, zero energy homes face both technical and market barriers. Once installed on the campus of the University of South Florida, the FLeX house will begin to challenge these hurdles by becoming the core of the Zero Energy House Learning Center, or ZEHLC. The ZEHLC mission is to promote the use energy efficient building practices for central Florida through teaching, learning, and research. Students of Various disciplines will collaborate with researchers and building industry professionals to operate, monitor and assist with teaching both other students and the public at large.

The building will demonstrate the use of active solar technologies, used in concert with the existing city grid. The system will send power back to the grid during peak load periods and draw from the grid during periods of low production. The net energy usage of the building will be zero or better. The building performance will be monitored over a long period of time for benefit/cost analysis and grid interactions.

The project seeks to develop new approaches to energy efficiency in buildings through an assimilation of current know-how and innovation with a multi disciplinary team of experts together with agencies including the Department of Energy, The Florida Solar Energy Center, and the USGBC and building industry partners. The latest advances in building components, passive systems and home energy end users will all be studied and demonstrated.

The latest in PV and PHEV, Bio fuels and fuel cell technology will be combined with “Zero Energy Home” technology in a systems approach that holds promise for the development of new products in the building, renewable energy and transportation industries adding jobs to the Florida economy and bringing Industry closer to the environmental goals of the state. Data Will be compiled which documents the initial cost of existing Zero Energy Homes and the payback period during which lower operating costs offset the initial investment to establish the current cost/benefit of energy efficient buildings and zero energy home Technologies. The Learning center will be monitored for an extended period to document its specific cost/ benefit.


All planned activities in the project will come from in-state vendors. Construction will be aided by Florida builders, contractors and trades. Analysis will be done by FSEC, aided by USF students. Florida utilities, utility planners and the public service commission will indirectly benefit from the collected information illustrating possibilities on a larger scale. New technologies and building strategies displayed in the Learning Center may encourage the development of new kinds of businesses and industries associated with energy efficient building and renewable energy technologies.

The Learning Center will become the focus, testing ground and source of data for new interdisciplinary curriculums in architecture and engineering and business based on the many factors involved in building energy efficiency and renewable energy technologies and how they relate to other economic and environmental issues.

3.2 ZEHLC OUTCOMES The Zero Energy House Learning Center will be a high

visibility project showcasing the University of South Florida and the State of Florida’s commitment to energy efficiency and

renewable energy on one of the largest campuses in the state. A successful project can be expected to result in an expanding niche market for ZEH that could flourish with the pressure of higher future energy prices. An accessible and well publicized learning center will raise awareness of energy efficiency and ZEH technologies among students, faculty, builders, local governments, local utilities, planners and statewide policy makers. Data gathered from energy monitors within the Learning Center will bring awareness to energy use and how it matches the renewable energy source. At a broader scale, the facility will serve as a demonstration to public utilities commissioners of how such buildings could influence Florida’s energy future. Enhanced awareness will lead to higher energy efficiency building standards and increased ZEH production across the state. The new businesses and industries that emerge around ZEH production will bring new jobs and economic stimulus to the State of Florida. Public outreach, media coverage, publications and on-line resources will make the project available for the education of the wider public. Such coverage and information on the project will illustrate to Florida citizens and the world how the ZEH concept is not futuristic, unreliable or inconvenient, but rather is readily achievable and affordable with greater indoor comfort and greater power reliability. The ZEHLC will be a flagship for sustainable design and a symbol of Florida’s commitment to energy research and Zero Energy design.

The ZEH Learning Center will make Zero energy home technology part of the awareness of thousands of USF students and many faculty and it will serve as an interactive learning device for the study and development of expertise in the areas of building energy efficiency, renewable energy sources and zero energy homes. With the backing of the FSEC and an interdisciplinary team, the ZEH learning Center Task will be coordinated with the 2011 solar decathlon held in Washington DC. The Solar Decathlon is the premier event internationally showcasing cutting edge ZEH technology and will bring international recognition to the University of South Florida as a leader in the field.

CONCLUSION The FLeX house is a flagship for sustainable design in

Central Florida’s hot, humid climate. Built upon the bones of its vernacular predecessors, FLeX is an elegant comingling of passive and active solar design, sustainable design practices, and regional design intelligence. It is a modern house which uses the material acumen of its region to create a rich and healthy environment for living, while providing an appropriate sense of place for its region. FLeX avoids the temptation of placing high tech devices upon a normative gabled box, and instead creates a bold architectural statement based upon the fundamental tenets of sustainability. Once built, FLeX will become the core of the Zero Energy House Learning Center on the campus of the University of South Florida, and will begin its mission to serve as a sustainable research and education center, and shining example of the future of Floridian housing.

FIGURE 7 Exploded diagram revealing extendable bedroom and entrymodules, galvanized corrugated steel envelope with large operablewindows, steel frame for the solar umbrella, umbrella louvers andsolar panels



ACKNOWLEDGEMENTS Research on FLeX House and the ZEHLC is being funded by a grant from the Florida Energy Systems consortium. Arduino.cc used under Creative Commons License Processing.org used under Creative Commons License JeeNode used under Creative Commons License

REFERENCES [1]Domin, C., King J., “Paul Rudolph the Florida Houses",

Princeton Architectural Press New York, 2002 [2]Hasse, R.W., Classic Cracker: Florida's Wood Frame

Vernacular Architecture, Pineapple Press Inc., Sarasota Florida, 1992

[3]Howey, J., “The Sarasota School of Architecture”, MIT Press, Cambridge Mass., 1995

[4] Parker D.S., “Very Low Energy Homes in the United States: Perspectives on Performance From Measured Data”, PDF, Florida Solar Energy Center website, Cocoa Fl., 2008, Information on http://securedb.fsec.ucf.edu/pub/pub_search

[5] Oberg, V., and D.Y.Goswami. 1998. A Review of Liquid Desiccant Cooling. Advances in Solar Energy 12: 346-385. American Solar Energy Society, Boulder, Colorado.

[6] Mago, P., and Goswami, D.Y., 2003, “A Study of the Performance of a Hybrid Liquid Desiccant Cooling System Using Lithium Chloride,” ASME Journal of Solar Energy Engineering, Vol. 125, No. 1, pp. 129-131.

[7] Fumo, N., and Goswami, D.Y., 2002, “Study of an Aqueous Lithium Chloride Desiccant System: Air Dehumidification and Desiccant Regeneration.” Solar Energy Journal, Vol. 72, No. 4, pp. 351-361.

[8] Fox, Michael, and Miles Kemp. Interactive architecture. New York: Princeton Architectural Press, 2009.

[9] Massachusetts Institute of Technology Media Laboratory. Media House Project. Barcelona: IAAC, 2004.

[10] Eiden, Joshua M. “Investigation Into The Effects Of Real‐Time, In‐Home Feedback To Conserve Energy In Residential Applications ,” PDF, current cost website, Lincoln, NE, 2019, Information on http://www.currentcost.net/University%20of%20Nebraska.pdf

[11] Aldous, d.e. and Aldous , m.d. 2008. Intrinsic and Extrinsic Parameters in Designing Therapeutic Landscapes for Special Populations and Uses. Acta hort. 775:99-105 http://www.actahort.org/books/775/775_11.htm



ANNEX A

HOMENET PACKET FORMAT DESCRIPTIONS Packet Length: Sending the packet length first allows the serial port orwireless radio to know how many bytes of data to look for.

Packet Version: This allows future changes to the protocol without breakingbackwards compatibility

Packet Type: Currently there are three supported types: 00: TCP-- Reliability is required. Nodes send a reply or an ACK packet back to the sender to acknowledge that it was received. This way lost packets can be resent or an error is generated and logged. 01: UDP‐‐ Reliability is not required. This is for sensors that regularly report data and the occasional lost data isn't a concern. 10: Broadcast-- A packet is sent to all nodes until it's time to live (TTL) becomes 0 . The To Devices field serves as TTL and the To Node field serves as an optional Group ID . ACK flag: Marks that a packet is a reply to a previous packet. The packet contains an extra byte after the ID containing the ID of the previous packet.

Encrypted Flag: Encryption hasn’t been implemented yet but AES encryption is planned. When this flag is set, it means that the rest of the packet is encrypted starting with the “FromNode” field. AES Encryption is done in 128bit (16 byte) blocks so smaller payloads will require padding. To account for this, there is an addition byte added after the ID to indicate the new payload size and any excess space inside the block is filled with random data.

Automatic/Manual flag: This flag marks when a packet is a manual user override versus one that is sent automatically by a device. This way if someone manually turns a light on, the system has to check if it has permission to override a manual setting in order to perform tasks such as the turning off of a light off after 30 minutes of illumination.

Priority flag: This flag marks when a packet should take priority over other packets. Some actions like a light switch turning on a LED light need to happen immediately where as others like sensors reporting scheduled data can be deferred a few seconds without harm.

To/From Node: The node address 0‐4095 (0x0 to 0xFFF in hexadecimal) Some typical addresses: 0xFF (255) is usually the primary Public Node, 0xFFF (4095) is usually the primary Master Node (like HomeNet.me)

To/From Device: Nodes will rarely have a just a single device attached. These field provides a standard way of accessing different devices attached to a node. Device 0 is always the node it's self for accessing battery level and other node properties

Packet ID: This allows the node to tell the difference between two identical packets received in close proximity. It also ensures that even identical encrypted packets will look different.

ACK/Reply ID: This contains the id of the previous packet that the node is replying to so the sender node can confirm that the packet it sent arrived intact and it knows that this packets contains the response.

Command: The command informs the node how to process the data that the payload contains.

Payload: This part of the packet contains the data being sent and can be up to 48 bytes long.

Checksum: This provides a fast way to validate that the packet arrived intact and without errors.



ANNEX B

SENSORS Room Sensors

A room can be made smart by installing just a single device that has collection of different sensors. It adds additional functionality to a smoke detector that would already need to be installed.

Occupancy Sensor: Detect when people are actually in a room. When the room is empty lights can be turned off and the HVAC system adjusted.

Light Sensor: Lighting in the room can be adjusted based on natural light. Based on other sensors, blinds could be opened or additional lights turned on.

Sound Sensor: Adjust the volume of media in different rooms, or listen for voice commands

Temperature Sensor: Serves as a thermostat for HVAC system so that room is only heated and cooled as much as needed.

Flame/Smoke Sensor, Carbon Monoxide: Can trigger alerts and alarms throughout the house if something dangerous is detected

Access Control

In a smart house it becomes economical to implement robust access control that used to be only available to businesses and institutions.

Digital Keys: Keys can be individually coded so that lost keys are merely an inconvenience and not a security concern

Wireless Fob: Inspired by remote unlocking for your car, it brings the same convenience to your front door

Cell phone: Your cell phone can act like a key, letting you unlock the door for yourself or friends who are locked out. It is inspired is by the new apps that automobile manufacturers are building.

Others: RFID, Keypad, Swipe Card, Biometric Access. The possibilities are limitless. Many choices are available based on convenience or amount of security desired.

Window: Contains sensors to let you know if it is closed and locked or trigger an alarm if it is shattered. Sensors are integrated directly into the frame of the window, simplifying the installation process and making it harder for security measures to be sabotaged. In combination with other devices, it

could alert you if window is open when AC should be on or let you know that the window is open and it's about to rain. Window blinds and louvers can be controlled maximizing the use of natural light.

Smart Power Outlet

Enables the Remote control and energy monitoring of power outlets. The system can turn them off if no one is home and has a built in power monitor that can report exactly how much energy you are using.

Weather Station

Get a precise weather forecast. It has a range of sensors like temperature, humidity, barometric pressure, anemometer (wind speed), wind vane (wind direction), a rain gauge and more. It can help determine whether to water the lawn or wait a day and see if it rains. It can monitor outdoor air quality and pollen counts and recommend when it's a good day to open the windows. All of the meteorological data it generates can be shared on the cloud to help build better weather forecasts the whole community.

Home Power Generation

Monitor your home's power production from solar panels. Track your power production from your cell phone. Quickly detect when a panel is underperforming and needs maintenance.

Smart Appliances

Monitor their performance and health to prevent untimely break downs. Appliances can get real‐time power rates and can choose to defer energy use until off‐peak times in exchange for a reduced power rate. For example, if you drive an electric car and it takes 6 hours to charge, you will hook it to charge when you get home but it could defer charging several hours until off peak and still be ready by morning.

Lighting

Lighting can be tied to sensors in the room so only as much light as needed is used. Smart home network also enables cool new lighting opportunities like using RGB LED's that contain a red, green and blue LEDS to reproduce almost any color that you can set from your cell phone.


Documents

54549 FLEX HOUSE ES2011-54