Pioneer of solar greenhouses in Australia and Japan

ClearVue Technologies, a smart building materials company, provides an update on the progress of a solar greenhouse experiment at Murdoch University and the progress of a commercial solar greenhouse installation in Japan.

The energy production and energy efficiency of ClearVue’s photovoltaic glass at Murdoch University Greenhouse have been continuously measured since the greenhouse officially opened on April 19, 2021.

The greenhouse consists of four glazed areas and an enclosed unglazed preparation area at the rear (south). The four areas include one area with plain glass to create a scientific “control” as a baseline against which to measure the performance of ClearVue glass relative to a conventional greenhouse.

The other three rooms in the greenhouse consist of three different versions of ClearVue PV glazing technology. The second chamber uses the commercially available ClearVue glazing product while the third and fourth chambers are variants of this product with different amounts of nano and microparticles to consider improving power generation and affecting plant growth dynamics.

Trial stages
ClearVue’s in-house technical team managed the data collection for energy efficiency and capacity tests.

For plant science research, ClearVue collaborated with Murdoch University professor Chengdao Li, a molecular geneticist, and his team, including Hao Luo, under a joint research agreement.

Li’s team looked at agronomic and physiological characteristics recorded from germination to harvest to understand the plant’s response to light filtered by ClearVue solar panels.

In this context, some plants need at least some ultraviolet (UV) light while others do better with little ultraviolet (UV) light. Other plants require different levels of visible light transmission. The goal of the first phase trial was to begin the search for the right balance of an ideal growth environment while maximizing energy production and savings.

As expected, different plants in different growth stages reacted differently to the light passing through the solar glass panels, removing a large amount of ultraviolet and infrared (IR) light due to the solar glass panels using these wavelengths to generate energy. .

For the purposes of the three components of the experiment, the ClearVue Greenhouse is equipped with an array of sensors that record and present a series of real-time data that provide scientists with accurate information about conditions such as temperature, humidity and the actual amount of light at all wavelengths received by plants.

This information was analyzed to make automatic adjustments to lighting, heating and cooling, screens and fans, among others, which in turn allowed the scientists to maintain a constant microclimate to provide optimal growing conditions, part of which is fed by the energy generated. by ClearVue glass applied to the greenhouse itself.

trial limits
The four chambers of the greenhouse were divided using expanded polystyrene (or EPS) insulated cooling panels and the eastern and western ends of the greenhouse were closed with EPS to obtain (as close as possible) four consistent chambers for the experiment.

The effect of this on the overall experience of all rooms is the loss of light (in all wavelengths) entering the greenhouse, and an ordinary commercial greenhouse (such as a solar greenhouse under construction in Japan) would not have such internal barriers to the ingress of light and incidental solar energy through your greenhouse.

This important limitation became apparent at the beginning of the experiment and could only be overcome by building four separate adjacent greenhouses or by using clear polycarbonate or plain glass partitions. These would have been less reliable in data collection and would have also allowed more natural light to reach factories, resulting in a less accurate measure of the energy efficiency savings than the ClearVue product.

In addition, it should be noted that the greenhouse is a research greenhouse and the back (south side) of the greenhouse has an unglazed science preparation area that extends behind all four growing areas, which means that there is no light coming from this side, unlike the situation Natural commercial spaces. A greenhouse is usually not the case and all sides of the structure will be glazed, allowing maximum daylight.

Another effect on the accuracy of data collection was that the vent valves in all rooms were not operating properly during the experiment; Three spaces remained closed and one space remained open. They were repaired and maintenance carried out prior to the second phase tests.

The focus of the tests is to measure the energy efficiency and energy savings of ClearVue glass and the energy generated by the glazing. This focus has resulted in the careful monitoring and control of air conditioning and fans in each area of ​​the greenhouse, resulting in automatic shutdown of those systems where no cooling or heating is required to maximize overall energy savings. This approach, despite its rationale, ignores the importance of indoor air circulation in a closed greenhouse environment. Air circulation is critical in a greenhouse for plant pollination as there are no natural insect pollinators.

Read the full study here.