Answer:
Not possible.
Explanation:
According to second law of thermodynamics, the maximum efficiency any heat engine could achieve is Carnot Efficiency η defined by:
[tex]\eta=1-\frac{T_{cold}}{T_{hot}}[/tex]
Where
[tex]T_{hot}[/tex] and [tex]T_{cold}[/tex] are temperature (in Kelvin) of heat source and heatsink respectively
In our case (I will be using K = 273+°C) :
[tex]\eta=1-\frac{-27+273}{14+273}\\=0.1428[/tex]
In percentage, this is 14.28% efficiency, which is the maximum theoretical efficiency any heat engine could have while working between -27 and 14 °C temperature. Any claim of more efficient heat engine between these 2 temperature are violates the second law of thermodynamics. Therefore, the claim must be false.
