L18 - Novel Solar Thermal Technologies

Question 1

Why is it also important to pay attention to clean heat energy?

Answer 1

Electricity and heat contribute to over 50% of global CO2 emissions

Question 2

What are the benefits of collecting the PV waste heat?

Answer 2

> 70% of the solar energy is dissipated as waste heat

Coolers are used to cool the PV modules during a sunny day; heat pipes are used to transfer heat and can be used to heat up homes or solar drying.

Question 3

Construction of thermally-coupled PVT collectors

Answer 3

GN

Question 4

The limits of thermally-coupled PVT collecters

Answer 4

In conventional PVT, the thermal absorber is thermally coupled with the PV module

Compromising the PV efficiency if pursuing a higher temperature thermal output.

The output temperature is limited to 60-80 degrees celsius which is too low for industry applications (100 - 400 degrees)

Question 5

Ways to spectrally seperate the solar spectrum in SSPVT

Answer 5

GN

Question 6

How to select the optimal optical filter and PV material for a SSPVT collector?

Answer 6

For picking optical filters, we are looking for a material which is transparent and is a blackbody.

Water is a common example, with a transparency of 250-1100 nm and black in >1100nm range.

We also depend on w, which is the weight coefficient, which converts the thermal energy to an equivalent amount of electricity and reflects the worth of thermal energy relative to that electricity.

Question 7

The working principle of nanofluids and nanofilms in SSPVT

Answer 7

Nanofilm:

TiO2/SiO2 nanofilm can spectrally seperate the solar spectrum into two parts.

This is because the layers are alternatively packed together as a coating in which the TiO2 film layers have a higher refractive index than the SiO2 film layers.

Question 8

Advantages of semi-transparent PV (SPV) based SSPVT

Answer 8

• No additional optical filter
• Simpler Structure
• No negative influence on PV effiency