黑洞社区

Skip to main content
Skip to navigation

Table 1
听	Initial capital cost (£)	Saving (%)	Operating cost (£)	Saving (%)	Whole life cost (£)	Whole life saving (%)
听		听	(over 30 years)	听	听	听
Pre-insulated	听	听	听	听	听	听
ductwork	37,000	21.5	67,672	20.4	104,672	20.8
Insulated	听	听	听	听	听	听
galvanised	听	听	听	听	听	听
sheet metal	47,154	听	85,058	听	132,212	听

Table 2
Velocity (m/s)	Cross-sectional	Flow rate (l/s)	Flow rate plus galv	Flow rate plus rigid	Reduction in	Reduction in
听	area (m²)	听	sheet steel ductwork	phenolic pre-insulated	flow rate (%)	fan power (%)
听	听	听	leakage (l/s)	ductwork leakage (l/s)	听	听
5	0.36	1800	2168.05	1811.04	16.5	41.7
7.5	0.36	2700	3068.05	2711.04	11.6	31.0
10	0.36	3600	3968.05	3611.04	9.0	24.6