Transmissive microfluidic active cooling for concentrator photovoltaics

•Transmissive CPV active cooling is developed for hybrid spectrum-splitting CPV/T.•100 μm deep transmissive microchannels are fabricated and field-tested.•The transmissive microchannels reduce the CPV module transmittance by only 5.2%.•The maximum CPV cell temperature is measured as 69 °C, well below the 110 °C limit.•The transmissive CPV active cooling performs stably during week-long outdoor tests.