You’re right. But, is it possible to connect a heating element with 400V * 16A by using e.g. L1+L2 instead of L1+N (230V * 16A). This would give me more heating power. Any ideas?
I can fully appreciate your reasons for wanting to go for the 2.5kw element, they are common here even if I see most brewers looking for a 3kw instead. The danger I suppose is that in offering 3.2kw some brewers may be drawn to that one judging it to be close enough!
I know you can’t account for stupid decisions but it might be worthwhile including in your product listing a mention that they should not be used on UK 13A fittings etc.
Dean.
The elements are custom, so I could offer a 2800W too probably. What would you consider the perfect element?
Are there any guide lines anywhere for recommended element power for a given batch size? There are plenty of calculators available to calculate how long it will take to change the temperature of a given volume by a given amount but what sort of time should we be aiming for? Also what sort of power is required to maintain a vigorous rolling boil for a given volume?
I’m doing BIAB (single pot) at this stage so same element for mashing and boiling. Aiming for 30L batches (60L pot).
I think the deciding factor is the temperature ramp that you can achieve.
Heat capacity of water is 4.2 kJ per degree per liter.
So for your 30L, with a 2800W element, you would get:
4.2 kilojoule / (liter * kelvin) * 30 liter / 2800W = 45 s / K
I used kelvin here because with Kelvin you can just copy/paste this into google. But apart from the offset, Kelvin is equal to Celsius.
So 45 seconds per degree.
I think for your mash steps you want to aim for max 1 min/degree, so that a 10 degree step takes max 10 minutes to achieve. With a HERMS setup, you’ll be heating your HLT and your mash tun with 1 element, so you are probably heating double the amount of water.
Keeping a rolling boil is no problem, it is getting there that requires power.
In the end it just comes down to: the max your power circuits can handle. You can always run the element at lower power with PWM.
Okay, new plan:
- 2800W@230V foldback element, 280mm + 240mm, Watt density 11.8 W/cm2 (fits 30 cm kettle)
- 3200W@230V foldback element, 330mm + 290mm, Watt density 11 W/cm2 (fits 35 cm kettle)
- 5000W@230V Ripple element, curvy, Watt density 14 W/cm2 (fits 40 cm kettle)
About 3 phase elements:
Even a 10 kW element would keep the current under 16A per phase. Anyone in the market for really big elements?
8500W to keep it under 13A.
Elco I really would like 3phase heaters. I thought about 6kw in HLT and around 4,5kw in Boil Kettle. Maby its overkill in Hlt but being able to raise temp fast just cut off alot of time during a brewday. Can you calculate how much watt a boil kettle needs to keep a good boil with 60 liters? But even tho less is more then enough then i would prefer lots of watt to raise temp and then PWM it to a good boil.
The domestic mains power supply in Australia is 240V AC, 50Hz. Standard 3-pin earthed power outlets are rated at 10Amps and are usually switched. The 3-flat-pin plug is used in all States of Australia (including its external territories), New Zealand, Papua New Guinea and Solomon Islands.
Most Australian switchboards have provision for 15Amps and 32Amps but require heavier wiring to be run to the GPO and a matching face plate with larger earth pin. Just changing the GPO(PowerPoint) in original setups is dangerous if the wiring is not the right gauge.
Regarding the PWM / 10% comment, in practice (e.g. in your preliminary sous-vide experiment) how many times per minute are the SSRs being switched once you’ve reached a temperature goal? And what is the impact to the rest of the service on the same circuit? For example, assuming the pumps are on the same circuit do they suffer from all that switching or do they basically not feel any effect?
I wouldnt drive pumps and brewpi on same circuit as heating elements, ill driwe those on a seperatly 3phase connection. but in theory there should be plenty overhead, and no problem doing so.
I’m not concerned about power overhead in the circuit, but I am concerned about frequent on-and-off cycling of a high load such as a 6000W electric heater.
I only seen flickering in light etc if there isnt much overhead, thats why I wrote it. To answer your question regarding how offent the SSR turns on, you got several variables, insulations, lid on, brewing in a kettle or iglo-cooler etc. My system turns on once, maby twice every 5 min to maintain temp, atm im building a new system with double walled kettles with insulation between. that proberly gives me one or two heating cycles every 30min… atleast thats the goal 