Update 2021-09-07-design-of-the-koji-room-koji-muro.md

Added captions and twitter link

Author: daizu27

_posts/2021-09-07-design-of-the-koji-room-koji-muro.md

@@ -114,6 +114,7 @@ This is a 1-dimensional heat transfer problem. If we pick 4-inch polyurethane wi
 If the indoor conditions are maintained at 30°C, we can further demonstrate that the heat losses through the wall will total **764W**. To keep the room warm, an equal amount of heat must be supplied. Let's illustrate the conditions of the koji room at time t=0 after inoculation, during which the koji generates no heat and all openings to the room are closed:
 
 ![](/assets/images/koji_room/01kojiroominitial.png)
+*Heat balance of the koji room immediately after inoculation*
 
 ### 3. Ventilation
 
@@ -125,11 +126,12 @@ First, consider the requirements for **heat removal**. We can show that our 300k
 
 
 ![](/assets/images/koji_room/02kojiroomheat.png)
-
+*Heat balance of the koji room with ventilation sized for heat removal*
 
 Next, let's consider the requirements for **moisture removal**. About 80% of the heat generated by koji is lost as water vapour, with the remaining 20% lost due to other effects. At the peak of its heat generation, we can show that the our 300kg of koji will emit 2.16kg of water per hour (see Appendix - Step 5). By exchanging moist indoor air with dry, outdoor air, we can show that a ventilation rate of **119m³/h** is necessary to remove the moisture emitted by koji.
 
 ![](/assets/images/koji_room/03kojiroomwater.png)
+*Mass balance of the koji room with ventilation sized for moisture removal*
 
 Finally, let's consider the requirements for **carbon dioxide removal**. Koji has a respiratory coefficient of around 1.0 throughout its entire process, which means that the koji's peak heat generation of 1623W equates to a CO₂ generation rate of 0.3m³ CO₂/h (see Appendix - Step 6) using the aerobic metabolism equation:
 
@@ -140,7 +142,7 @@ $$
 If we maintain an indoor carbon dioxide concentration at 4500ppm, which is 500ppm below the OSHA Permissible Exposure Limit (PEL = 5000ppm), and assume an outdoor CO₂ concentration of 500ppm, we can show that the flow rate necessary to remove all generated carbon dioxide is **76m³/h.**
 
 ![](/assets/images/koji_room/04kojiroomCO2.png)
-
+*Mass balance of the koji room with ventilation sized for carbon dioxide removal*
 
 Comparing the three ventilation rates, we can see that **moisture removal**, at 119m³/h, is the limiting design criteria in our scenario.
 
@@ -149,6 +151,7 @@ Comparing the three ventilation rates, we can see that **moisture removal**, at
 Knowing that our maximum ventilation rate will be **119m³/h**, let's size the heating panels of the koji-room. Our conductive heat losses are 764W, and ventilating fresh air at 119m³/h removes 2480W of heat. Our koji generates 1623W of heat at its peak, so our heater must provide at least 1621W of heat (see Appendix - Step 7):
 
 ![](/assets/images/koji_room/05kojiroomfinal.png)
+*Final heat balance the koji room with ventilation with ventilation sized for moisture removal*
 
 And that's it! At t=0h, our heaters will be running at 764W and our ventilation turned off; and at the peak of growth, our heaters will be running at 1459W and our ventilation at 119m³/h. This is our operating window, and every other point in time will fall somewhere between these two extremes. Achieving steady conditions is the job of whatever **control system** we select. This can range from a basic thermostat and humidistat to a programmable controller.
 
@@ -241,7 +244,7 @@ And finally here's the best picture I could find of a koji room online, which is
 
 There are a lot more details difficult to cover in one post, but hopefully this will give you an idea of how to size, construct, and operate a koji room (*koji muro*), and even how to build some of the simpler koji-making machines. 
 
-If you plan on constructing a koji room, or have constructed one already, I'd love to hear about it! Feel free to reach out to me on twitter @Keeifa
+If you plan on constructing a koji room, or have constructed one already, I'd love to hear about it! Feel free to reach out to me on twitter [@Keeifa](https://twitter.com/Keeifa)
 
 This post is part of an ongoing effort to translate Japanese koji-related literature to the west. If you're interested in this, feel free to reach out to me as well. 
 
@@ -280,6 +283,8 @@ The design basis will be for a koji room with the following conditions:
 
 Air flows in this post are using a dry air basis at 30°C / 70% RH (indoor conditions). 
 
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+
 #### Step 2 - Determine the koji amount, dry weight, and room dimensions. 
 
 The weight of steamed rice at inoculation (hiki-komi) will be 300kg. If the unsoaked white rice has a moisture of 13%, and the water absorption ratio at inoculation is 34%, the actual water content of the koji is:
@@ -290,6 +295,8 @@ This is in agreement with Table 1. Thus the dry weight of the steamed rice is 19
 
 Let the depth of koji be 5cm. Based on Table 1, 300kg of steamed rice will occupy approximately 660L or 0.66m³ in volume and require a table with an area of 13.2 square meters (geometric calculations not shown). Let's select a 5.3m x 2.5m table. To allow for clearance and the storage of other items, let's select a room of 8m (L) x 5m (W). Finally, a ceiling height of 2.0-2.2m is standard - we will select 2.2m (H).
 
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+
 #### Step 3 - Determine heat loss through the room walls, and check for condensation 
 
 1-D steady state heat transfer through a wall is given by the following equation:
@@ -456,4 +463,4 @@ Q_{heater} = 1621W
 $$
 
 
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