Performance of Unglazed Transpired Solar Collectors

1
Performance of Unglazed Transpired Solar
Collectors

• Steve Ray
• April 26, 2002

2
Overview

• Active System
• Air Heating
• Fan Assist
• Air Heating Applications
• Where outdoor air is required
• Large area
• Large air volume

3
Overview

• Many Existing Installations
• 300 to 100,000 square feet
• GM, Ford, Federal Express
• Patented by Conserval Engineering
• Solarwall

4
Overview

• Ford Plant, Ontario
• Golden, Co

5
Basic Principles

• Energy Balance
• Collector
• Qsol Qradw Qconvc Qradc
• Qconvc m x cp x (Tp Ta)
• Building Wall
• Qcond Qconvw Qradw
• Qconvw m x cp x (Tr Tp)

6
System Model

• Many simulations have been run from energy
  balance along with actual data from existing
  installations
• Solar Efficiency is 70
• Model Based on Efficiency
• Qu It x ? x Ac
• Qload m x cp x (Ts Ta)

7
Simulation

• Collector Size
• GM Battery Plant
• Constant Temp
• Fan runs 24/7
• Collector bypassed in summer
• Cost based on Retrofit Installation

8
Program Output
9
Economics
10
Economic Comparisons
11
Conclusions

• System is effective as a pre-heater
• Best suited for high outside air building
• Industrial / Commercial
• Model fits with DOE data
• More specific to particular locations since TMY2
  files are used
• Economically viable in some areas
• New construction is even better
• Gaining acceptance across industries

12
References

• Principles of Solar Engineering
• Goswani, Kreith, Kreider
• Thermal Simulation and Economic Assessment of UTC
  systems
• David N. Summers
• MEE-573 Lecture Notes
• J. Kelly Kissock
• DOE
• Conserval Engineering (Solarwall.com)