Examveda

Sensible heat factor is given by (where SHR = Sensible Heat Ratio and LHR = Latent Heat Ratio)

A. $$\frac{{{\text{SHR}}}}{{{\text{SHR}} + {\text{LHR}}}}$$

B. $$\frac{{{\text{SHR}} + {\text{LHR}}}}{{{\text{SHR}}}}$$

C. $$\frac{{{\text{LHR}} - {\text{SHR}}}}{{{\text{SHR}}}}$$

D. $$\frac{{{\text{SHR}}}}{{{\text{LHR}} - {\text{SHR}}}}$$

Answer: Option A

Solution (By Examveda Team)

Sensible Heat Ratio (SHR) - is used to describe the ratio of sensible heat load to total heat load and can be expressed as:
$$\eqalign{ & {\text{SHR}} = \frac{{{{\text{q}}_{\text{s}}}}}{{{{\text{q}}_{\text{t}}}}} \cr & = \frac{{{{\text{q}}_{\text{s}}}}}{{{{\text{q}}_{\text{s}}} + {{\text{q}}_l}}}......\left( {\text{1}} \right) \cr} $$
where,
SHR = sensible heat ratio (ratio of sensible heat load to total heat load)
$${{{\text{q}}_{\text{s}}}}$$ = sensible heat load (kW, Btu/hr)
$${{{\text{q}}_{\text{t}}}}$$ = total heat load - sensible heat and latent heat (kW, Btu/hr)
$${{{\text{q}}_l}}$$ = latent heat load (kW, Btu/hr)
For an air flow (1) can be modified to:
$${\text{SHR}} = \frac{{{{\text{c}}_{\text{p}}}\left( {{{\text{t}}_{\text{o}}} - {{\text{t}}_{\text{i}}}} \right)}}{{{{\text{h}}_{\text{o}}} - {{\text{h}}_{\text{i}}}}}......\left( {\text{2}} \right)$$
where,
$${{{\text{c}}_{\text{p}}}}$$ = specific heat air (1.005 kJ/kg°C, 0.240 Btu/lb°F)
$${{{\text{t}}_{\text{o}}}}$$ = outlet air temperature (°C, °F)
$${{{\text{t}}_{\text{i}}}}$$ = inlet air temperature (°C, °F)
$${{{\text{h}}_{\text{o}}}}$$ = outlet moist air enthalpy (kJ/kg, Btu/lb)
$${{{\text{h}}_{\text{i}}}}$$ = inlet moist air enthalpy (kJ/kg, Btu/lb)

This Question Belongs to Mechanical Engineering >> Heat And Mass Transfer

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