4/21/2020 2:39 PM | |
Posts: 46 Rating:
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Hi Betel, I tryd to understand your solution for the Energy meter. As i understood you used some work arounds due to limitations of the Logo 0BA5. I use a Logo 8.2 12/24RCE 6ED1 052-1MD08-0BA0, and i was wondering if there was a way to make the Energy meter more compact and easyer. For my application i want to calculate the COP of a heat pump to heat up a Jacuzzi. There fore i need the heat in kwh that the heat pump suply to the Jacuzi. I have a flow sensor 1puls=0.084l and at in and output of the heatpump 2 PT100 4-20mA 0-100°C At start up the water teperature is 7°C and the setpoint is 39°C Via a bypass valve we try to maintain to have a delta T between the in and output of 2°C The flow can varie very slow between 40 and 60l/min but does not fluctuate all the time. Once the jaccuzi has reached the setpoint the heatpump works one ore 2 times/hour. We mesure also the electrical consumption of the heatpump and we mesure the outside temperature. Hope you can get me on the way to create a energy meter for this application ------------------------------------------------------------------------------------------ |
Last edited by: Jen_Moderator at: 04/22/2020 09:42:21New subject after splitting |
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4/21/2020 6:05 PM | |
Joined: 2/22/2008 Last visit: 8/6/2024 Posts: 2698 Rating:
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Maybe this Link will help you. This seems to be exactly your application. Regards, Scorp |
4/22/2020 10:32 AM | |
Joined: 2/22/2008 Last visit: 8/6/2024 Posts: 2698 Rating:
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Have you looked into my Link or are you not interested ? |
4/22/2020 11:10 PM | |
Joined: 2/22/2008 Last visit: 8/6/2024 Posts: 2698 Rating:
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There are different ways to optimize the calculation, this depends on your sensor and the application. The problem is the maximum integer of the Logo arithmetic (+32767) With 11-12 Impulses per Liter you will have a more inaccurate result for lower flowing. Have you some values like typical flow, maximum flow, typical temperature difference and maximum temperature difference ? I think, you must have the same formula for your heat pump. Q = m * c * dT, Q=Power [kW] m=Flow [l/s] c = 4.19 [kJ/l*K] dT=t2-t1 [K] Maximum Q is 32767W=32.767kW or you lose the last digit, then Q=32767x10W=327.67kW and so on. If you have some values for me, i can make a base program with some comments simular to the program on the linked side. Regards, Scorp P.S. I have prepared a first version with your values, if i have understand correct. AttachmentCOP1.zip (238 Downloads) |
Last edited by: Scorp at: 04/23/2020 07:14:54Last edited by: Scorp at: 04/23/2020 08:38:32 |
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4/23/2020 10:43 AM | |
Joined: 2/22/2008 Last visit: 8/6/2024 Posts: 2698 Rating:
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With these values you can use power in W, because 60 l/min = 1 l/s and dT=2 K (°C) you have a maximum of 8400 W (< 32767). See next version with proper values for this and an additional datalog every day at the time 00:00. You can build the differences for each day and week in an excel sheet. If you want to display a historie on the Logo, then you must expand the counters for daily, weekly ... hours as you need. Simulate first my program directly, e.g. type in 300 (30.0°C) for AI1, 290 (29.0°C) for AI2 and 12 (frequency 11.78 Hz = 1 l/s = 60 l/min) for I5 to see the power 4190 W in AM3 (Aq output of B004). For display only use the blocks B004 for power, B005 for flow, B047,B069,B078 for temperatures and B011,B012 for energy. Regards, Scorp AttachmentCOP2.zip (231 Downloads) |
Last edited by: Scorp at: 04/24/2020 09:42:17 |
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