2nd law of thermodynamics heat pump problem

[hazzz]

Homework Statement

Here is the problem:

An inventor claims to have developed a heat pump that provides a 180 kW heating effect for a
293 K household while only consuming 70 kW of power and using a heat source at 273 K. Can this
claim be possible?

Homework Equations

COP of heat pump = Qh/W
COP of heat pump (carnot max) = Th/(Th-Tl)
n (thermal efficiency) = W/Qh = 1-(Ql/Qh)
n(max carnot) = 1- (Tl/Th)

The Attempt at a Solution

The answer to this problem is that the claim is valid because the COP of the heat pump is less than the COP max, I just want to know can I use thermal efficiency instead of COP to see if this claim is valid?

 

[BvU]

Well, what is the definition of the COP ?
Cengel CH 6 has plenty examples (check 6-78)