Case study on COHEAT delivering our first heat network as complete newbies in this industry

1. Case study: a 55/35C heat network
Marko Cosic
Technical Director
marko@coheat.co.uk
+44 7774 524 114
Rehau District Heating Workshop at the Building Centre, 23rd March 2017

2. Standard practice (£350 + £30-50/MWh)

3. A heat network

4. Buy the cookbook?

5. Follow the recipe?

6. Which recipe?
(courtesy of Michael Kaare Jensen, Danfoss Market Development Director, SmartReFlex seminar, Milan 16/11/2015)
http://www.smartreflex.eu/fileadmin/user_upload/Danfoss__Milan__16Nov2015.pdf

7. What are the numbers?
• Say 50 homes @ 70 m2 each with 3.5 occupants
• SDHA: 115 kW
– F101:2008 lookup table: 0.61 Litres/sec at 10/55C = 115 kW
– F101:2004 has the equation for deriving the table
• DS439: 210 kW
– 1.19*50+18.8*500.5+17.6 (kW)
– Note this is heat exchanger size not expected load
• BS6700:2009: 450 kW
– ~450 kW if 32.3 kW per home.
– BS6700 is withdrawn/replaced by EN 806. The negligent still use it…

8. Industry guidance? (Euroheat & Power)
(courtesy of Euroheat & Power)
https://www.euroheat.org/wp-content/uploads/2008/04/Euroheat-Power-Guidelines-District-Heating-Substations-2008.pdf

9. Field data? DCW: Northumbria University
(courtesy of Jess Tindall “Are we significantly oversizing domestic water systems?” presentation)
http://www.cibse.org/getmedia/a97b6dfe-5bc8-4214-a20d-38247bb0fc85/063-Tindall-Slides.pdf.aspx

10. Field data? DHW: Energy Saving Trust

11. Load profiles are straightforward

12. Network design needs statistical analysis
• Blue columns
– “What % of the time
is spent at this
power output? (zero
power removed for
clarity)
• Red curve
– “What % of the time
(when there is any
hot water use) is the
hot water power
lower than X kW per
home?

13. Sample time is extremely important
5 seconds or 5 minutes? 12.3 kW or 8.3 kW?

14. Eat, sleep, compute, repeat
N choose r, compute for selected N for a variety of sample periods

15. What are the real diversity factors?
15
(prototype hardware)
(chart smoothed – do not use as design reference)
0.0
50.0
100.0
150.0
200.0
250.0
1 10 100
Power(kW)
Number of homes
DS439
EST 5-sec
REDAN
SDHA
EST 5-Min

16. Which recipe?
(courtesy of Michael Kaare Jensen, Danfoss Market Development Director, SmartReFlex seminar, Milan 16/11/2015)
http://www.smartreflex.eu/fileadmin/user_upload/Danfoss__Milan__16Nov2015.pdf

17. A heat network
Traditional instrumentation and control

18. How do we improve heat networks?
• Know what customers are asking for
• Know what the whole system is doing
• Know what customers are receiving
• Control how the whole system operates

19. A smart heat network

20. Demonstration network

21. A user interface
(prototype hardware)

22. Ring Ethernet and Linux backbone
(prototype hardware)

23. Networked energy centre (heat supply)
(prototype hardware)
(before insulation)

24. Distribution network (25 mm twinpipe)
12 homes, 120 metres
20 mm ID, 500 kPa peak dP
Peak space heat @ 55/35
Peak DHW @ 55/25

25. Networked heat interface unit (HIU)
(prototype hardware)
(before insulation)

26. Networked radiators and room sensors
(prototype hardware)
(open source)

27. System performance
• Interim figures:
• (usage: 3 MWh/home/yr)
• (losses: 0.3 MWh/home/yr)

28. Charts (March 9th 2016 @ 2-7C ambient)

29. What do customers ask for? (space heat)
29
(prototype hardware)

30. Textbook heating schedule

31. Consumer heating schedule

32. What is happening? (now)
32

33. What happened before? (engineers)

34. What happened before? (accountants)
34

35. What did we deliver? (space heat)
(prototype hardware)

36. See radiator balancing

37. Radiator valves (some practicalities)

38. See other things
38
Towels/underwear on radiator House party

39. See problems “I’m cold”
39

40. What did we deliver? (hot water: meter)

41. What did we deliver (hot water: actual)

42. Why might we care? (bypass)

43. Real time control
• What is the system being asked for now?
– Interrupt driven
– Integrated with service level policy
• Create a plan
– Quickly and reliably
– Handles constraints
• Implement the plan
– Delegates control authority

44. Real time planner

45. Real time service priority

46. Aggressive dP control
Available pump capacity (%)
(differential pressure = 0 kPa for 12 hrs/day)

47. Predictive control
• Where am I now?
– Historic data, physics model, state estimator
• What am I being asked for next?
– Heating schedule, keep-hot schedule
• What else matters?
– Weather forecast
– Hot water demand forecast
– Cost model for consumer comfort / tapping delays
– Cost model for operating the network
• What should I do next?
– Calculate a plan for the real time planner to implement
– Share the plan with other services on the platform

48. Model predictive control in action

49. Sharing information with the consumer

50. Marko Cosic
Technical Director
marko@coheat.co.uk
+44 7774 524 114
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Thank you