Abstract Solar air heaters are seen as a promising option for reducing the building energy demand in particular when combined with heat pumps。 In this work, a modeling tool to predict the performances of heat pump driven by solar heater is developed。 In particular, the channel between the base of the roof and the tiles is considered。 As a case study, a detached house in northern Italy is taken into consideration。 Results show that the air temperature variation ranges from 2 °C to 20 °C leading to a heat recovered between 2 kW and 7 kW in winter and summer time, respectively。 There is no significant variation of air temperature and heat recovered between the two considered orientation (N-S and E-W), whilst the integration of the PV cell in the tile reduces the thermal energy by 15%。 The heat recovered enhances the heat pump COP reducing the Primary Energy Consumption of a conventional heat pump by 5% achieved with limited additional costs。 The impact of the electricity generated is more important also because the excess can be sold to the grid and not wasted as for the heat recovered in summer time。84893

Keywords: Solar driven heat pump, solar heater, Primary Energy savings, PV tile

Nomenclature

α Absorptivity

β isobaric thermal expansion coefficient [K-1]

ε emissivity

γ cell power temperature coefficient [%/°C]

ρ Density [kg m-3]

θ Incidence angle [°]

el Average electricity generation Efficiency [%]

is,c Isentropic efficiency of the compressor

a,b Friction factor parameters

A Tile area [m2]

BIPV Building Integrated Photovoltaic

BIPV/T Building Integrated Photovoltaic Thermal

c Specific Heat Capacity [kJ kg-1 K-1]

Conv Conventional tile case

COP Coefficient of Performances

Dh Hydraulic Diameter [m]

E Energy [J]

EPI Energy Performance Index

DNI Direct Normal Irradiation [kWh y-1 m-2]

f Friction factor

G Solar Irradiance [W m-2]

GHI Global Horizontal Irradiation [kWh y-1 m-2]

h heat transfer coefficient [W m-2K-1]

k Conductive heat coefficient [W m-1 K-1]

Serenity index

kΔp Pressure drop constant [bar m-2 s2]

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L Length of the pitch [m]

m Mass flow [kg s-1]

Nu Nusselt Number

p Pressure [bar]

P Electric Power [W]

PEC Primary Energy Consumption

Pr Prandtl number

PV Photovoltaic tile case

Thermal power [W]

R Pressure drop term [J/kg]