Case study: a 55/35C heat network

Transcription

1 Marko Cosic Technical Director Case study: a 55/35C heat network Rehau District Heating Workshop at the Building Centre, 23 rd March 2017

2 Standard practice ( /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) Milan 16Nov2015.pdf

7 What are the numbers? Say m 2 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* * (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 BS6700 is withdrawn/replaced by EN 806.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)

9 Field data? DCW: Northumbria University (courtesy of Jess Tindall Are we significantly oversizing domestic water systems? presentation)

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 Power (kw) What are the real diversity factors? DS439 EST 5-sec REDAN SDHA (prototype hardware) EST 5-Min Number of homes (chart smoothed do not use as design reference) 15

16 Which recipe? (courtesy of Michael Kaare Jensen, Danfoss Market Development Director, SmartReFlex seminar, Milan 16/11/2015) 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 55/35 Peak 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 9 th 2-7C ambient)

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

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 Towels/underwear on radiator House party 38

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 Thank you For more information, please contact: Marko Cosic Technical Director