A hybrid solar air photovoltaic thermal collector including: a solar photovoltaic panel having a plurality of photovoltaic cells for receiving solar radiation, a heat transfer apparatus including: air passages (16a, 18a) for air to flow into, through or out of the heat transfer apparatus, wherein the air passages include multiple air passages, chambers or plenums through which air flows during use, and air flow modification means configured to direct air flow to transfer heat to or from a rear of the solar PV panel, the air flow modification means including: an array of jets, air nozzles or orifices (22, 116) provided in a flow path between at least one air passage, chamber or plenum of the heat transfer apparatus and the rear of the solar PV panel, characterised in that said jets, nozzles or orifices (22, 116) are arranged to direct the air flow from the at least one air passage, chamber or plenum at the rear of the solar PV panel to enable/enhance cooling of the solar PV panel, and at least one drain (26, 118) to enable removal of air after impinging on the rear of the solar PV panel from the array of jets, air nozzles or orifices, through at least one space between adjacent plenums and/or between at least one said plenum and a peripheral edge of the solar PV panel or mounting cassette, wherein the arrangement of the jets, air nozzles or orifices (22,116) delivers equal cooling potential through a series of said air plenums to each photovoltaic cell of the solar PV panel so as to provide a mean cell temperature of each cell is substantially identical to maximise electrical recovery. a solar photovoltaic panel having a plurality of photovoltaic cells for receiving solar radiation, a heat transfer apparatus including: air passages (16a, 18a) for air to flow into, through or out of the heat transfer apparatus, wherein the air passages include multiple air passages, chambers or plenums through which air flows during use, and air flow modification means configured to direct air flow to transfer heat to or from a rear of the solar PV panel, the air flow modification means including: an array of jets, air nozzles or orifices (22, 116) provided in a flow path between at least one air passage, chamber or plenum of the heat transfer apparatus and the rear of the solar PV panel, characterised in that said jets, nozzles or orifices (22, 116) are arranged to direct the air flow from the at least one air passage, chamber or plenum at the rear of the solar PV panel to enable/enhance cooling of the solar PV panel, and at least one drain (26, 118) to enable removal of air after impinging on the rear of the solar PV panel from the array of jets, air nozzles or orifices, through at least one space between adjacent plenums and/or between at least one said plenum and a peripheral edge of the solar PV panel or mounting cassette, wherein the arrangement of the jets, air nozzles or orifices (22,116) delivers equal cooling potential through a series of said air plenums to each photovoltaic cell of the solar PV panel so as to provide a mean cell temperature of each cell is substantially identical to maximise electrical recovery. air passages (16a, 18a) for air to flow into, through or out of the heat transfer apparatus, wherein the air passages include multiple air passages, chambers or plenums through which air flows during use, and air flow modification means configured to direct air flow to transfer heat to or from a rear of the solar PV panel, the air flow modification means including: an array of jets, air nozzles or orifices (22, 116) provided in a flow path between at least one air passage, chamber or plenum of the heat transfer apparatus and the rear of the solar PV panel, characterised in that said jets, nozzles or orifices (22, 116) are arranged to direct the air flow from the at least one air passage, chamber or plenum at the rear of the solar PV panel to enable/enhance cooling of the solar PV panel, and at least one drain (26, 118) to enable removal of air after impinging on the rear of the solar PV panel from the array of jets, air nozzles or orifices, through at least one space between adjacent plenums and/or between at least one said plenum and a peripheral edge of the solar PV panel or mounting cassette, wherein the arrangement of the jets, air nozzles or orifices (22,116) delivers equal cooling potential through a series of said air plenums to each photovoltaic cell of the solar PV panel so as to provide a mean cell temperature of each cell is substantially identical to maximise electrical recovery. an array of jets, air nozzles or orifices (22, 116) provided in a flow path between at least one air passage, chamber or plenum of the heat transfer apparatus and the rear of the solar PV panel, characterised in that said jets, nozzles or orifices (22, 116) are arranged to direct the air flow from the at least one air passage, chamber or plenum at the rear of the solar PV panel to enable/enhance cooling of the solar PV panel, and at least one drain (26, 118) to enable removal of air after impinging on the rear of the solar PV panel from the array of jets, air nozzles or orifices, through at least one space between adjacent plenums and/or between at least one said plenum and a peripheral edge of the solar PV panel or mounting cassette, wherein the arrangement of the jets, air nozzles or orifices (22,116) delivers equal cooling potential through a series of said air plenums to each photovoltaic cell of the solar PV panel so as to provide a mean cell temperature of each cell is substantially identical to maximise electrical recovery.