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Completed Research: RP-1710, February 2020

RP-1710, Effects of Dynamic Shading Devices on Daylighting and Energy Performance of Perimeter Zones

From eSociety, February 2020

In a recent ASHRAE Research Report, Kristen Cetin, Ph.D., P.E., Member ASHRAE, currently with Michigan State University, describes RP-1710 which evaluates, through full-scale experiments and testing, the effectiveness and energy savings potential of several types of commonly used dynamic shading devices coupled with electric lighting controls in perimeter office spaces with different types of glazing systems. This includes three specific objectives as discussed below: (a) Full-Scale Experimental Testing & Data Collection (b) Method for Evaluation of Energy Savings Potential & Occupant Comfort (c) Development and Testing of Control Algorithm(s).

1. What is the significance of this research?

The purpose of this research is to evaluate, through full-scale testing, the performance of three types of commonly used, dynamic interior shading devices coupled with electric lighting controls in east, south and west-facing perimeter office spaces. We specifically focused on evaluating the HVAC and lighting energy savings and visual comfort impacts associated with the use of these automated systems. Most of the research to date in this area has been based on energy and daylight simulation of such systems; very few full-scale testing efforts have been conducted. In addition, very little research has evaluated the performance of shading devices in the east and west orientation of a building. The results of this research provide experimental data and validated energy models and lighting models of these systems to support more accurate simulation capabilities.

2. Why is it important to explore this topic now?

Buildings are becoming more intelligent, with more controls and more automated capabilities. Automation, such as through the use of dynamic shading devices, supports improving the efficiency of our building environment while minimizing manual adjustments needed by occupants. The full-scale demonstration of such methods helps to confirm the findings of energy simulation estimates, as well as to identify real-world challenges with the execution of the use of such systems, ultimately leading to improved overall performance.

3. What lessons, facts and/or guidance can an engineer working in the field take away from this research?

The results of this work help to quantify the level of lighting and HVAC energy savings that can be achieved based on a control set of full-scale tests. They also provide validated energy models and daylight models that can be used to quantify performance in different climate zones. An engineer could use these to determine to what extent the use of dynamic shading in a newly constructed or retrofitted building would be beneficial. In addition, the research report provides a list of lessons learned and recommendations for the selection and implementation of dynamic shading devices, control algorithm implementation and sensor setup. An engineer could use these guidelines and suggestions in selecting a control algorithm and dynamic shading setup for a building they are designing or retrofitting.

4. How can this research further the industry’s knowledge on this topic?

This research supports improved knowledge on the full-scale performance of dynamic shading devices under a range of different environmental conditions, including exterior wall orientation, shading device type, window type, sky conditions, control strategy, etc. As new devices, automation and controls are introduced into buildings, research such as this project can help to support the industry with detailed knowledge and guidance on their use.

5. Were there any surprises or unforeseen challenges for you when preparing this research?

As with any experimental research project, there are unforeseen challenges that occur throughout a project. This particular project required several iterations of adjustments to the control strategies to reduce the number of small adjustments to the shading device height/angle to minimize the level of distraction to occupants, while still maintaining a visually comfortable indoor environment.