|Sponsor||Student Researchers||Goals and Objectives||Executive Summary||Final Report|
Habitat for Humanity is a nonprofit organization founded in 1976 on the belief that any person should have a right to a simple, durable place to live, and that decent shelter in decent communities should be a matter of conscience and action to all. Since 1976, Habitat has grown to become one of the largest and most visible nonprofit organizations in the country, building or repairing hundreds of thousands of homes, and helping millions of people around the world.
Habitat for Humanity is supported by their local ReStores, retail stores dedicated to selling donated furniture, home accessories, and building materials. Instead of placing these donations directly in new homes, all profits from the ReStore sales are used to fund Habitat’s local building projects. These ReStores are crucial to Habitat for Humanity as they provide its only reliable source of revenue. Habitat occasionally receives grant funds, but the pressure of funding a significant portion of their projects falls to the ReStores, and challenges them to resell as many goods as possible (Galvin, Arnone & Tate, 2014).
This project sought to propose an affordable energy solution to efficiently regulate the working environment for the customers, volunteers, and staff of the ReStore, and which would allow the facility to remain in operation during the summer months. Firstly, we identified the impact an environmental change will have on the ReStore’s customers, volunteers, and staff. Our team conducted in-person customer questionnaire surveying in order to assess the effects of temperature on the experiences and interactions of customers at the ReStore. We ascertained from the data collected using the survey that a significant percentage of ReStore customers have experienced high temperatures while at the facility, which have led to negative experiences. An even larger percentage of the survey participants responded that environmental conditions with lower temperature levels would contribute to a more positive experience while shopping at the ReStore. The other demographic that our team surveyed was ReStore volunteers and staff members. Individual interviews were conducted with volunteers and employees in order to understand the impact that current summer conditions have on their ability to do their work and their motivation while working. Analysis of the responses of the individual interviews showed that a majority of ReStore workers feel the summer temperatures inhibit their ability to work and their enthusiasm, which would be improved by maintaining a lower temperature in the warehouse. Notably, our team was also informed of the necessity of better air circulation and ventilation as several respondents indicated that it can become difficult to breathe while working within the ReStore in the summer.
Following data collection, we determined specific reasons the warehouse reaches high temperatures throughout the summer, and sought to correct these issues by conducting cooling load calculations and determining appropriate ventilation requirements. Our team began creating a ventilation solution by first seeking professional advice, analyzing which approach would best serve a warehouse of the ReStore’s size, and then performing calculations using ASHRAE handbooks to determine which specifications our system would need.
The experts we reached out to included professors at WPI as well as practicing Professional Engineers in the field of heating, ventilation, and air conditioning (HVAC). The professionals we met with recommended that we implement a night flush system, a technique that uses large ventilation fans to pull cool air into the building during the night. For the system to be effective in a retail warehouse, the HVAC specialists suggested an industry standard of six to ten complete air changes per hour. This target far exceeds the calculated minimum ventilation rate required by ASHRAE Standard 62.1.
Selecting supply and exhaust fans required careful consideration of variables including static pressures, loudness, weight and cost, required power draw, and maintenance accessibility. In calculating the cubic feet per minute (CFM) necessary for each intake and exhaust fan to achieve at least six air changes per hour, we discovered problems with rain penetration across the louvers. Our team adjusted our target air changes per hour to reduce the speed at which air flowed into the warehouse to compensate for this issue. Problems also emerged regarding the structural integrity of the building and its ability to support the additional weight of large ventilation fans. Our team’s leading concern however, was the fan’s ability to circulate air effectively enough to provide significant temperature reduction.
Fortunately, during our research we came across an alternative industrial-sized ventilation system. AIRMAX International offers a ventilation system which utilizes a large outdoor air-handling unit to circulate air through a ceiling-mounted fabric ductwork. An outdoor fan unit is ideal as it avoids any excessive noise and weight problems created by wall mounted propeller fans. Strategically placed holes in the fabric duct ensure that the air is evenly distributed and will not disturb shopping customers. The system is designed to spread air throughout the warehouse rapidly, replacing all the air in the building every six minutes. Thus, this design eliminates the possibility of areas without air movement or circulation, known as dead-zones.
The AIRMAX team will fabricate and install a 30,000 CFM makeup air system that will deliver ten air changes per hour at the floor level of the warehouse. This system also utilizes the night flush method and will allow the building to be as much as 20 degrees cooler in the morning, making the warehouse significantly more comfortable for employees, volunteers, and customers.
The AIRMAX unit is a renowned ventilation system that has been installed in hundreds of warehouses nationwide with proven results. Our team is confident the AIRMAX system will be the most beneficial climate control system for the ReStore to establish a retail friendly environment. Deborah Maruca Hoak, the ReStore Director, mentioned that in her three years of research prior to this project she has not found a system of equivalent capability. Perhaps the most advantageous aspect of the AIRMAX system is that it can be transported, and thus will remain an asset of Habitat for Humanity should they relocate the ReStore.
The total cost for the system including delivery, installation, and electrical connection will be $30,723.00. This price is comparable to the cost of supply and exhaust fans used in a traditional night flush; however, the AIRMAX system retains a verified track record of providing effective temperature reduction in large-scale warehouses.
Furthermore, the ReStore is required by their lease to insulate the walls of the warehouse, before the year 2017. We determined the optimal insulation option based on a cost analysis of materials and installation in order to provide the most economical solution to the ReStore. Insulation will not significantly reduce the temperature inside throughout the summer, but will reduce the heating costs for the ReStore by hundreds of dollars each month during the winter. The different insulation types our team considered for the ReStore were spray foam, rigid foam board, and blown-in. The Dow Chemical Company donates one inch rigid foam board to all Habitat for Humanity projects, leading to significantly reduced material costs. Rigid foam board can be difficult to install due to existing wiring and pipe work; however, volunteers are able to perform the installation, saving thousands in labor costs. Rigid foam board is the most logical choice based on cost effectiveness, thermal resistance, and installation application therefore was our recommendation to the ReStore.