Labview

It's winter break at UNH so i have a lot more free time to work on the brewery. Since I'm waiting on a number of parts to come in, I'm using this time to focus on the software aspect of the project. To run the brewery, I have decided to use LabVIEW.  Labview is a graphical programing environment where you can create virtual instruments to execute processes and  communicate with hardware. I will be creating a master virtual instrument(VI) that will control many sub-VI's that interface with the brewery. The process is quite detailed but for the purpose of this blog i will try to simplify it the best I can. Bear with me. The functions of these VI's can be broken down into three basic categories;   Input, Processing, and Output.

Input :
Input signals will consist of either user input, data acquisition from hardware, or output from a higher level VI.

Processing:
Data from inputs such as probes will need to be manipulated from varying voltages into usable information like temperature. The VI uses this information to determine how to proceed. For example, a Temp monitoring VI sees that a temperature is too low,  the VI would enable another sub-VI who's sole purpose is turning on the heater.

Output:
After the data is processed, the information is output either to the display to show the current levels and temps, or used to control a piece of hardware. For the case of turning on the heating element, the VI would tell the hardware interface module to output a logic high signal(3-5 volts DC). This signal is then used to switch the relay which applies the 240 volt AC to the element. 

The entire programing process relies heavily on the use of loops. ie IF this is true THEN do this, IF NOT do this, or WHILE this is true do this, etc. The graphical interface of LabVIEW uses block diagrams to represent these loops and processes and saves the user long nights of debugging code.

solenoids and solid state relays

All of the fluid transfers during the mashing process will be controlled by the computer which will open and close the solenoid valves and turn on and off the pump and heating element.  The valves are 304 Stainless Steel 1/2" npt  Solenoid Valves with viton seals from www.DudaDiesel.com.
These valve are normally closed and open only when 110 volts AC is applied.  To do this i will be using Solid State Relays or SSRs.  An SSR acts like an electrical switch.  The computer will put out a small dc voltage of about 5 volts which the SSR uses as a control signal that tells it to close the AC circuit and apply power to the valve. I will need 1 relay for each valve, the pump, and a special 40amp relay for the 240 volt heating element.     

Mashing Diagram with one pump

This diagram shows the system during its mashing program where the wort is pumped from the bottom of the mash/lauter tun through the coil in the hot liquor tun then redistributed over the grain bed.   My original design called for the use of 2 pumps however in an effort to save some money i will most likely go with a one pump design which should work just as well.  The short gray bars indicate temperature probe locations. The small gray cylinders are solenoid ball valves and the black bars are manual ball valves which means my design isn't 100% automatic however the mashing process will be which was my initial goal. This is also a cost saving measure and could be upgraded in the future.

Rims vs. Herms

This was a big decision when it came to my project; rims or herms? There are many different types of home brew mashing setups but the two most common are HERMS (Heat Exchange Re-circulating Mash System) and Rims (re-circulation infusion mash system). Both systems re-circulate the mash from the bottom to the top of the mash tun. the difference lies in the way the mash is heated to the desired temperature.  A HERMS system pumps the mash through a heat exchange (HEX) coil submersed in water in a hot liquor tun (HLT) heated by either an electric hot water heater coil or directly fired by a gas burner.  Whereas a RIMS system pumps the mash directly across a heating element contained in a section of pipe.  There are endless debates over the pros and cons of each, however I have chosen to go with a HERMS method mainly for the advantage of being able to use the water in the HTL as my sparge water when rinsing my grains.

Some Background Information

Taken from my project proposal....

"The problems I aim to solve with this project are the complications and inefficiencies of the infusion step mash process faced by many home brewers. The first step in brewing beer is the mashing process. This is when the grains are soaked in hot water to allow enzymes to convert the starches into fermentable sugars. While there are different methods of mashing the goal of the home-brewer is to achieve max efficiency and convert as much of the starches into sugars as possible. This will in turn reduce the required grain bill and save money for the brewer.  The most efficient process is known as step mashing.  For this process the grains are added to a certain amount of water at about 100 degrees.  The grains now referred to as “the mash” is then allowed to rest at this temperature for about 15 minutes. This is the also called the acid rest. Next the temperature of the mash is raised to around 122 degrees and allowed to rest again for about 30 minutes this is called the protein rest. Next the mash is raised to 140-150 degrees and rests for 45 minutes. This is the saccharification rest. Finally the mash is raised to 170 degrees and the sugary liquid referred to as wort is drained from the grains and into the boil kettle. The grain bed is now rinsed with 170 degree water in a process called sparging. This water rinses any remaining sugars from the grains and is collected in the boil kettle.

The problem with step mashing for the average homebrewer is achieving accurate temperatures at each step. Many rely on a method called infusion step mashing. This is when a certain measured amount of boiling water is added to the mash to achieve an equilibrium temperature equal to the next desired step temperature. This method is difficult to maintain accurately and involves many adjustments and temperature reading and results in fluctuating temperatures that can be harmful to the enzymes.

For my project I will design a system that will re circulate the wort from the mash tun through a heat exchanger and precisely maintain a set temperature.  The wort will be drawn from the bottom of the grain bed pumped through a coil immersed in the hot liquor tun where it will be heated then pumped back on top of the grain bed.  The entire system will be monitored and controlled from a laptop computer with all temperature steps and rests preprogrammed for the specific beer style.  The temperatures of the system will be monitored at multiple points and used to control relays to turn on or off the heater.  The pumps and valves for wort transfer and sparging will also be controlled by the system. I will need to design methods to monitor water levels and ph levels as well as temperature.  All information will be logged and used to report efficiency of the system and for reference for future use.  " 

During the course of this project I intend to try to explain the brewing process to the best of my knowledge but I'd like to point out that I'm not any sort of expert when it comes to brewing beer. I've been brewing for about 2 years now and probably have about 15 batches under my belt so far and only 4 of those have been all-grain* batches. However it only took me a couple of day long all-grain brew sessions to realize that step infusion mashing as way too much work and frustration.   

*All-grain brewing refers to the process explained above where the home brewer mashes the grains to produce the sweet wort. An easier alternative is extract brewing, where the brewer adds concentrated malt syrup or powder to water and then boils as usual.  Extract brewing is the starting point for most home brewers as it is relatively inexpensive to get started as it requires far less equipment and can be done on the kitchen stove. Extract brewing is fairly simple and can produce excellent beers however it limits the extent of creativity when it comes to selecting different grains.

Senior Project

Hello, My name is John Burdett and I am a senior electrical engineering student at the University of New Hampshire. As a requirement for graduation, I will be presenting a senior engineering design project at the UNH Undergraduate Research Conference in April 2011. For this project I have chosen to design and build an automated e-herms (electric heat exchange re-circulating mash system) brewery. I feel this project will incorporate many different areas of electrical engineering study and combine the knowledge I have gained from my courses at the University of New Hampshire with my own personal interests in home brewing. I am creating this blog to track my progress along the way, and as a means of providing updates to my friends, advisers, and sponsors all of whom I'd like to thank in advance for their support.