correct value/unit for HW cylinder standing loss kWh/l.day vs kWh/24hrs
Posted: Fri Feb 05, 2016 3:58 pm
Hi. Been getting confused re this due to lots of different units / terminology being thrown around in various guidance docs and support texts. Essentially in ApacheSystems> Hotwater i've entered a value for HW cylinder storage loss of (in this case) 0.0075 kWh/(l.day) but on running Compliance (SBEM) the scroll text in the command line popup window says something line 'check standing loss as value indicates abnormal level of insulation'
The above figure was derived from an example of 1.57kWh/day standing loss for a 210 litre cylinder (Megaflo Eco, 60mm factory insulant). So 1.57 / 210 should give losses in units of kWh/litre.day Seemed a reasonable approach to me.. but then I get the error reported above...
So checking lots of guidance, such as for VE compliance (for example http://www.iesve.com/downloads/help/The ... liance.pdf section 7.2.6) suggests that this is actually an entry for 'DHW storage tank loss factor' and that this should be calculated from the combination of 'storage loss factor' x 'volume factor Vf' . If I was to take the closest entries for 60mm insulant(0.0152) and 210volume (0.817) then 0.0152x0.817 gives 0.012 factor which is totally different. Can someone please clarify this for me?
By the way, strangely the orginal figure above (0.0075) also gets rounded to 0.002 in the BRUKL report. ( Why...? )
The above figure was derived from an example of 1.57kWh/day standing loss for a 210 litre cylinder (Megaflo Eco, 60mm factory insulant). So 1.57 / 210 should give losses in units of kWh/litre.day Seemed a reasonable approach to me.. but then I get the error reported above...
So checking lots of guidance, such as for VE compliance (for example http://www.iesve.com/downloads/help/The ... liance.pdf section 7.2.6) suggests that this is actually an entry for 'DHW storage tank loss factor' and that this should be calculated from the combination of 'storage loss factor' x 'volume factor Vf' . If I was to take the closest entries for 60mm insulant(0.0152) and 210volume (0.817) then 0.0152x0.817 gives 0.012 factor which is totally different. Can someone please clarify this for me?
By the way, strangely the orginal figure above (0.0075) also gets rounded to 0.002 in the BRUKL report. ( Why...? )