Grantee Research Project Results

2015 Progress Report: Heating Attic Air for Space Heating and Dryer Applications Using Solar Thermal

EPA Grant Number: SU835329
Title: Heating Attic Air for Space Heating and Dryer Applications Using Solar Thermal
Investigators: Tam, Kawai , Alcaraz, Christian , Mak, Samantha , Rolf, Julianne , Schoeman, Ryan , Morales, Sergio , Nguyen, Julie , Tan, Patrick , Tatyanich, Anna , Milbes, Huda , Evans, Reginald , Riehn, Robin , Mendiola, Rachel , Mohammed, Shahid
Current Investigators: Tam, Kawai , Vu, Samantha , Leyva, Juan , Coria, Vanessa , Rodriguez, Giancarlo , Sanders, Brandon , Parker, Jonathan , Kim, Ji Hwan
Institution: University of California - Riverside
EPA Project Officer: Hahn, Intaek
Phase: II
Project Period: August 15, 2012 through August 14, 2014 (Extended to August 14, 2017)
Project Period Covered by this Report: August 15, 2014 through August 14,2015
Project Amount: $89,933
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet - Phase 2 (2012) Recipients Lists
Research Category: Pollution Prevention/Sustainable Development , P3 Awards , P3 Challenge Area - Air Quality , P3 Challenge Area - Sustainable and Healthy Communities , Sustainable and Healthy Communities

Objective:

The solar powered thermal closet is an alternative unit for humidifying, space heating and drying clothes. Ambient air is drawn and heated before being funneled through a solar thermal collector on the roof of a home. The solar collector houses aluminum pipes that are exposed to the sun through two transparent tempered glass panes. Through a series of inline duct fans, the hot air is directed to the bottom of the solar thermal closet and from there it vertically rises through the closet, drying clothes and escaping to the exterior or is directed to the interior for space heating or humidifying when required. The unit is to be automated with microcontrollers to better control space heating and clothes drying via a user-friendly LCD interface. In addition, temperature and humidity data is recorded in the microcontroller to provide users with energy saving information for a set period of time. The objectives in Phase 2 include building and testing the dryer closet at Victory Gardens in Moreno Valley, CA, data collection of the system throughout the year in different seasons, optimization of the unit for both clothes drying and space heating through design features such as drying efficiency, safety, ergonomics and implementation of touch-screen user-friendly controllers.

Progress Summary:

The current team has taken over the project from the previous team that was in-charge during the 2014-2015 academic year. The previous team was responsible for coming up with a new solar thermal collector design. The new solar collector design is more space efficient; the left and right sides can be transported in two separate sections and secured when on site (Figure 1). This year’s team is currently overseeing the construction of this solar collector which is being built by UCR’s Machine Shop. The previous team also tested the dryer that was built for the installation at Victory Gardens. Testing was carried out on a sunny day and a cloudy day to measure the performance of the closet dryer. Results of this testing are shown in Table 1. Drying under cloudy conditions was done in fan-only mode using a floral dress, and drying under sunny conditions was done with solar thermal heat using jeans, sweatshirts, T-shirts, and a jacket.

Figure 1. Two-piece solar collector.

Table 1: Drying Data

Conditions	Sunny Day	Cloudy Day
Ambient Temperature	27°C	21°C
Closet Inlet Temperature	60°C	21°C
% of water removed after 90 minutes	86.7%	100%

At UCR’s community garden (R’Garden), a 7′ ´ 7′ Rubbermaid tool shed has been built for the testing of the new solar collector design. To allow for leveling out the terrain, a gravel foundation of ½-inch rock gravel was placed underneath the shed. The shed has been insulated with 2.5 inches of R-tech insulating sheathing on the inside of all four walls of the shed, giving an R-rating of 16.7 on each wall, simulating a house. A smaller Rubbermaid tool shed has been constructed and placed inside the larger toolshed to act as a closet for accurate testing of the solar collector designs and electronic systems. The inside walls and ceiling of the closet are insulated with 2.5 inches of insulating sheathing. The tool shed will have the new solar collector added on the south-facing roof, angled towards the sun, where it will be bolted down on an insulated frame attached to the plastic roofing. Insulated dryer ducting will be used for the transfer of the heated air from the solar collector to the closet inside the tool shed.

Figure 2. Toolshed in R’ Garden

The permit that was needed to allow the construction of the solar thermal closet in the resident’s home at Victory Gardens was delayed over the winter and spring months, but was finally approved by the city of Moreno Valley this summer. With the approval of the building permit, the construction of the closet section of the integrated appliances system has begun. Collaboration between the contractor and the team members has led to the most effective placement of humidity and motion sensors along the framing of the system. Two humidity sensors will be placed at a height of four feet from the closet floor, alongside the inner framing, and the motion sensor will be placed on the floor nearest the entrance to the closet.

The contractor has poured the cement foundation, erected the metal framework, and secured the outdoor walls of the closet. In the next coming months he will remove a section of the homeowner's wall that the closet is adjacent to, allowing for access to the closet from the inside of the home. After completing the installation of the inline fans, air ducting for the inlet feed of air, and insulation on the inner walls of the closet, the doors will be constructed and fastened to the closet; completing the closet system.

In addition to the closet, the contractor will begin installing the solar collector on the roof of the home. The solar collector will be set on a metal frame and fastened to the house, and angled towards the sun. Once the ducting is installed and the closet is fitted with shelving, the keyboard and monitor of the controller will be fastened to the wall inside the home near the closet. With the electrical system ready to go, the closet will be ready to dry clothes and provide data for optimizing the system.

The prototype for the control system is currently programmed on a Raspberry Pi, shown in Figure 3 and will be used in the tool shed installation in the R’Garden. A prototype PCB (PC board) for the final installation at Victory Gardens will be put into production within the next few weeks. An overview of the current design is shown in Figure 4. So far the prototype successfully integrates all sensors and components and logs the necessary data onto a SD card. The plans for improving the system include development of a more robust prototype and automatically logging data through Bluetooth.

Figure 3. Raspberry Pi Microcontroller

Figure 4. Overview of PCB Design

Future Activities:

A new team of senior students comprising of three chemical engineers, a computer engineer and a business student has been formed to continue working on the project in order to enhance the features of the appliance unit. A multi-disciplinary team plays a critical role in helping to analyze the feasibility, marketability and enhancement of the system from different perspectives. This team is currently working to get the construction of a dryer closet unit completed at Victory Gardens in Moreno valley since receiving approval from the City of Moreno Valley in July of 2015.

The business student has been added to help the engineers make enhancements by considering factors such as user-friendliness, user expectations and a more thorough cost analysis so that the project has a strong potential for adoption by the market. This is essential because our goal is to replace electric tumbler dryers with solar thermal drying units so that we can shift our dependency from electric appliances to appliances that run on a renewable source of energy. We envision the solar thermal dryer unit as a future appliance which would be a part of housing communities in the future.

Journal Articles:

No journal articles submitted with this report: View all 1 publications for this project

Supplemental Keywords:

Alternatives, residential, home improvement, green construction, innovative technology, pollution prevention, ambient air, renewable, public good, cost-benefit

Progress and Final Reports:

Original Abstract

P3 Phase I:

Heating Attic Air Using Solar Thermal Energy for Space Heating and Drying Applications | Final Report

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The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.