Environmental Engineering Reference
Table 3 presents the main design characteristics of the heat pipe recoverer that has been
built. The tube bundle consists of 4 pipes per row, and three rows. The configuration chosen
is done taking into account boundary layer limitations. In order to decrease the convection
heat transfer resistance between the air and the heat pipes, both in the impulse air area as well
as the return air area, fins perpendicular to the heat pipes are located parallel to the air flow,
and built of layers of an aluminium-manganese alloy within which the heat pipes are inserted.
Table 3. Design characteristics of the heat pipe device
Maximum heat output (W) 85
Pipe length (m) 0.62
Pipe wall thickness (m) 2.1 × 10− 3
Wick type 350, smooth
Wick porosity (m 2 ) 5.3 × 10− 11
Wick material: Stainless steel
Inner radius (m 2 ) 10.6 × 10− 3
Working fluid water
E XPERIMENTAL I NSTALLATION
Experiments were developed in the Air Conditioning Laboratory at the University of
Valladolid, Spain. As mentioned, the system is located in a recovery configuration to
condition a room. The recovery system plus the conditioned room takes up approximately 20
The systems used to carry out the trials are the following: (Figure 7 -8)
Supply system: this has a fan with a potentiometer to keep the air flows under
Air Handling Unit (A.H.U.): this equipment allows us to simulate the conditions of
the air supplied (temperature and humidity).
Air distributing System: all the measuring instruments are inserted here.
Water distribution System: there is a water pump to which a rotameter is joined. The
system also has a pressure spray system with downward directed nozzles and a water
droplet remover to avoid water loss.
A porous evaporative cooler with energy recovery. (E.C.)
A heat pipe device with energy recovery. (H.P.)
The conditioned room: the dimensions are 2x2x2.5 m, which contains an air to air
reversible heat pump inside to guarantee when needed necessary that the space is
Monitoring and Data-Acquisition system: a computer monitors and stores all the
results from the measuring instruments.
From the A.H.U. the air goes inside the EC. This main airstream is called the primary
airstream and when this airstream is conditioned in the SIEC it goes to the HP and after
passing through this device it enters the room. As was mentioned the system is located in a