Page 14

Technical System Catalogue Climate Control

Air/air heat exchangers Project planning Calculate the specific thermal output of the heat exchanger: . qw = QV – (A ΔT k) ΔT Selection diagram 25 20 15 10 5 0 12 30 10 8 A 6 ΔT 40 4 2 50 0 60 70 3000 2000 1000 0 10 20 30 40 50 60 70 80 . QV qw Note: ΔT = Temperature difference (K) For ambient temperatures that are lower than the desired. Qv = Heat loss (W) enclosure internal temperature, the use of air/air heat qw = Specific thermal output (W/K) exchangers may be appropriate, particularly in cases where A = Enclosure surface area to IEC 890 (m2) there are dust, oil and aggressive substances in the ambi- k = Heat transfer coefficient (W/m2K) ent air which must not be allowed to ingress the enclosure for sheet steel k = 5.5 W/m2K under any circumstances. A temperature difference of 10 K between the ambient temperature and the enclosure internal temperature is ideal. Internal circuit – Wall-mounted units Attention should be paid to installed equipment that is fitted with its own ventilation system, such as blowers and axial fans. If their air flow is directed against the chilled air flow of the heat exchanger, the air may short-circuit, bypassing the component and adequate climate control would no longer be guaranteed. Note: Never direct the chilled air flow at active components. 3 - 13 Technical System Catalogue/Climate control


Technical System Catalogue Climate Control
To see the actual publication please follow the link above