Diversity

Danish

https://docs.google.com/spreadsheets/d/1TtprDWpiO6NmWu6S8g5v00gYaIJC5v9B30qqNb8nUSw/edit?usp=sharing

Studies

• File:Water Services calcs report.pdf
• File:Pipe sizing Luna.pdf

Live Anonymous Diversity

https://heatweb.fred.sensetecnic.com/api/public/graph/dhwload

This data provides 3 variables as standard, in one second resolution:

• DHW flow rate (litres/minute)
• DHW Power delivered (kW) based on mains at 10C and recorded output temperature
• How many systems running

Ways to Reduce Peak Load

• Shift heating load.
• Keep heating constant,
• Heating on earlier on the coldest days (optimum start), to avoid morning surge.
• Hot water cylinder.
• Set peak rate costs, from 7:30 to 8:30 on cold Winter weekdays.
• Peak rate on/off indicated to user so they can choose to avoid a peak rate time. No charge for draw-offs that start in cheap rate but continue into peak.
• Option to have heating linked to auto-off during peak times.
• Option to reduce DHW temperature at peak. Doesn't reduce load, but increases primary dT (reduces flow).

1st Diversity Field Trial

Below are three screen shots from two days in a row (days 8 & 9) of the total DHW loads from the 2 bed system been used to examine diversity for a retired couple.

The reason for posting it is, it demonstrates the theory nicely. You can spot the additional load from yesterday, with a new peak just after the highest peak. The peaks last approx 4 seconds each and are 10 minutes apart.

9 days of data - or 9 HIUs - gives a peak of 52kW against a potential peak of 342kW if all HIUs drew 38kW at the same time. Danish diversity gives 85kW. But this is too few HIUs to define a standard from.

If we want diversity up to say 1000 properties, then the proposition is:

Monitor 10 HIUs for 100 days gives you 1000 days of data from which you can create a standard for UK diversity, that is more relevant than the Danish standard referred to in guidance (but not yet translated into English).

Live system on http://heatweb.ddns.net:1881/diversity