Here are some pictures of my Electric HERMS brewing system. "HERMS" stands for Heat Exchanger Recirculating Mash System. The mash temperature is maintained or increased by recirculating the wort from the bottom of the Mash Tun, through the heat exchanger in the Hot Liquor Tank, and returned to the top of the mash. There is a 5500 watt electric heating element in the HLT which is being controlled base on the temperature of the wort leaving the heat exchanger.
The frame was welded up from 40' of 2"x2"x1/8" stainless tubing
The control panel has the two PID process temp controllers from Auber Industries, and 6 LED switches from Automation Direct. There is also an audible alarm mounted to the side which is triggered from the HLT controller. I use that to let me know when the HLT is up to temp. All of the control panel wiring is 24 volt with the exception of the power for the controllers. I attached the control panel to the stand with an easy swivel mount I made from a stainless pipe union.
The stainless steel electric panel houses a main disconnect, two 30 amp breakers for the elements, one 10 amp breaker for everything else. The elements are wired first to two pole 30 amp relays controlled by the switches on the control panel. Then one leg is wired to the elements and the other to SSR'S (solid state relays) which are controlled by the process controllers. The four other relays at the top control the two pumps (one future), the water fill solenoid valve, and the stirrer. There is also a speed controller for the stirrer mounted in the door. The electric panel is wired to the main house panel with a 50 amp GFCI breaker.
The stirrer was acquired on EBay. It is a Talboys laboratory overhead stirrer. I disassembled it and mounted the speed controller remotely. I bent up a piece of stainless for the bracket and mounted with double sided tape to the lid. The other blue wire is for the float switch.
The inside of the HLT you can see the 5500 watt element, the stainless prop on the stirrer, and the heat exchanger coil which is 25 feet of ½" convoluted copper from B3. The convoluted copper creates turbulence in the wort stream which improves the heat transfer.
All of the tubing is ½" ID ¾" OD silicone with a PET overbraid. The first line on the pump discharge is the bypass; the other is going to the heat exchanger in the HLT. On the pump return, one side comes from the HLT and the other from the MLT. You can also see the water fill going into the HLT through the check valve.
