Questions tagged [building-physics]

The physics of buildings, specifically thermal conduction, convection, & radiation; heating and cooling; ventilation; transmission and management of water vapour & pollutants

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36
votes
2answers
17k views

What is the purpose of these diversions in a natural gas line?

The campus where I work has a long covered walkway (~.5 mile) which has several labeled pipes running under the roof (chilled water, fuel oil, air...). All of the pipes run dead straight except for ...
17
votes
3answers
7k views

What is the most efficient means of warming a building with a high ceiling?

Consider a large auditorium, a church, or some other very large, essentially one roomed building with a high ceiling. Suppose that the building has many entrances which enable cold air in/hot air out ...
6
votes
7answers
767 views

How would you move a sail boat with no wind or paddles

If I stood on a sailing ship and had a very strong pair of lungs (possibly motorized) then if I blew the sail would I be able to move the ship forwards?
6
votes
1answer
101 views

Where to insulate Underfloor air distribution system in a temperate climate

I have a proposed underfloor air distribution system (UFAD) for a one level office in a temperate climate. Typically the demand for heating and cooling in this climate is about even for offices. ...
6
votes
2answers
60 views

Is a single large impact better than several small impacts for breaking ice

I'm designing a device that uses impact to remove ice from sidewalks. I have a question about how to best design the impact mechanism. I can design it to deliver several light impacts or fewer harder ...
5
votes
2answers
137 views

Recoil of hydraulic lift/elevator

I noticed that when a group of people enter in an hydraulic lift/elevator often when the last person steps in the lift/elevator has a small but noticeable recoil: the lift goes down a few mm then it ...
5
votes
1answer
85 views

What approaches are there for demolishing a structure and how is an approach chosen?

From my office on the 21st floor of a building in Vancouver, BC two parking garages in the process of being demolished are visible. A third is just out of view a few more blocks away. One of these ...
3
votes
3answers
936 views

Tower crane with a cabin on ground level

Pardon me for kind of a stupid question, but I keep wondering. Traditionally, tower cranes' cabins are located at the top of the tower. I can understand why it have been necessary up to ~1990s, when ...
3
votes
1answer
147 views

Recreating Focaults Pendulum

I am having issues building a recreation of Focaults Pendulum (basic, inexpensive, undergrad project). At this point, I am going to purchase aircraft cable or suspension cable unless someone can ...
3
votes
1answer
81 views

Where to start when studying Architectural Engineering by myself? [closed]

I have this idea of creating my own curriculum for studying Architectural Engineering. I aim at talking with actual architectural engineers in my surroundings and ask them for advice on the topics I ...
3
votes
1answer
162 views

Modeling rigid body dynamics: Trouble with equations, encountering nonsense answers

Hi, I am working on modeling a simple rigid body dynamic system through a certain range of motion. Here is the picture of the system. I am trying to solve the system for the variables $x_1'', y_1'', ...
3
votes
0answers
46 views

What is the minimum height of a chimney needed in a camper?

Like a lot of people nowadays, I'm fitting a log fire into the back of a camper van but can't find the minimum height above the roof for the chimney. Ideally, it should be as low as possible for ...
2
votes
1answer
409 views

What's the purpose of these small closet-like-rooms-without-a-door?

I was recently on the UCLA campus (University of California Los Angeles) and I saw the Bunche Hall. I love the design and the architecture of the building. However I saw a little (what I would call) a ...
2
votes
2answers
122 views

Cooling tower for nuclear power plants

Cooling towers for nuclear power plants often have the shape of a hyperboloid. At first glance, I thought that an obvious reason for this would be the smaller sectional area, meaning the tower would ...
2
votes
2answers
73 views

Can a horizontal foundation safeguard against earthquakes?

I have not taken any course in civil engineering. What I was taught was that a broad base would prevent something from toppling. So it makes me wondering instead of nailing the foundation of a ...
2
votes
1answer
1k views

Why don't we make bricks out of coffee grounds?

Okay, so I've noticed that a lot of people grind coffee, and a lot of companies grind it on an industrial scale. Having produced some of the drink we called coffee, a huge proportion of the mass of ...
2
votes
2answers
132 views

Can a crisscrossed metallic skeleton resist earthquakes for buildings?

To follow up with my previous question on the seismic design of buildings, I would like to ask if it makes sense to support buildings with strong thick 'crisscrossed' metallic frames. I have the ...
2
votes
1answer
342 views

Can a neutrally bouyant helium balloon be suspended in air using magnet entrapment?

The above picture is a basic concept of how a levitron toy works. Could the top floating peace stay entrapped in the magnetic field without having to spin if the edges of the balloon keep the top ...
2
votes
1answer
106 views

Controlled demolition of a sky scraper?

Sky scrapers are often found in dense urban environments. Is there a known method to controllably demolish a sky scraper with minimal collateral damage?
2
votes
3answers
116 views

Building a machine from an ideal physics problem

I have a physics professor for whom I'd like to build a machine. Featured in a problem he is notorious for assigning students, originally from Kleppner and Kolenkow's "Mechanics," the machine causes ...
2
votes
1answer
55 views

Investigating the potential of generating energy from moving water in pipes on a water production site

I work on a water production site, we have a staggering amount of water flowing, much of which is just using gravity pressure and feeding into reservoir tanks. (flow on various sites ranges from 100 ...
2
votes
1answer
36 views

Looking for something to reflect ultraviolet light at extremely low wavelengths

I have been working on a product that involves the reflection of low wavelengths of UV light (200-250nm). However, I have not come across many materials that are able to do so and the high-...
2
votes
0answers
52 views

What would happen if the air conditioning failed in a skyscraper for an extended period?

I'm writing some fiction which involves the AC in a modern glass curtain skyscraper (50-80 floors?) in an American city failing for a period of weeks, maybe even for up to two months. Could anybody ...
2
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0answers
22 views

One dimensional U-Factor Calculation - How to determine indoor / outdoor film resistances

Can someone clarify the ASHRAE Fundamental 2017 (SI Units) (See Below) Indoor and Outdoor film resistances. The manual states that it comes from Table 3 and in the description of table 3 it states &...
2
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0answers
14 views

Sun light illumination on a lower floor vs high building closely

there is an investor that wants to build very close to our building. In case we agree, the buildings will stand like on the pictures below, 3 meters apart from each other. I tried to draw them in ...
2
votes
0answers
12 views

Increase in target emission rate (TER) when using a air source heat pump (ASHP) in standard assessment procedure (SAP) calculation

I am running a SAP calculation on a proposed building which will be utilising a 8.5 kW ASHP for space and water heating. I am also running a comparative analysis against a mains gas boiler to show the ...
2
votes
0answers
27 views

How to ensure natural ventilation through a shaft?

I have a small shaft, 2.5m wide by 4m deep, sunk into the ground. Due to explosion protection I should ensure "natural ventilation" - this is the termgiven in the relevant ordinance, no air flow ...
2
votes
0answers
113 views

Mathematic modeling of an overshot water wheel [closed]

We're working on a project that require some mechanical engineering and electronics engineering. In this project we've to model this overshot water wheel (so the water comes from the left top side and ...
1
vote
2answers
243 views

Does attic insulation help cool a building?

Given that hot air rises, it's easy to understand how attic insulation can help keep a building warm; say, in the winter, for example. But when winter changes to summer, does the attic insulation help ...
1
vote
1answer
206 views

Rubber band Powered Free Flight Helicopter [closed]

I am building a free flight helicopter for a Science Olympiad competition, and the general rules are as such: https://www.soinc.org/sites/default/files/uploaded_files/Helicopters_2017_Diagram.pdf ...
1
vote
1answer
96 views

Inertial Forces while analysing forces on a Piston in a Slider - Crank Mechanism?

I get that we are analysing the Piston in a non-inertial frame of reference, but the point of my question is that according to D'Alembert's Principle, whenever an inertial force comes in the line of ...
1
vote
1answer
90 views

how would one calculate the % of heat not absorbed by a heat sink?

I'm planning on building a plant growth chamber inside a sealed/insulated 55 g rain barrel, and I'm trying to figure out how much of the heat from my lights will enter the chamber, and how much ...
1
vote
1answer
590 views

Reaction forces in a structure

I have the following structure, in which I am failing to calculate the two reactions: Cz (apparently vertical) and Dz, in the roller support of the beam. The beam length is 7.5 m, the reactions Az, Cx,...
1
vote
1answer
133 views

Dimensionless Thickness

I have encounter this notion: "Dimensionless Thickness". Does anyone have any idea how to interpret this? One can find such a term here. My interpretation is that the name comes from the fact that ...
1
vote
3answers
104 views

Can temperature gradient keep concrete wall below 100% RH in 100% RH atmosphere?

Consider a high and wide concrete wall of say 30 cm thickness, covered with a sheet of vapor barrier on one side, and a sheet of say 30 cm thick and effective insulation on the other side. The vapor ...
1
vote
0answers
25 views

Heat storage mass vs. AIR in an ICF house

If we would want to build a family house (ICF) regarding operational costs, should we leave the insulation on the inside, or should we remove it from the inside? If we would remove it, the walls ...
1
vote
0answers
170 views

equivalent full hours of heating equipment

I would like to know if there is a standard way of calculating the equivalent to a capacity factor but for heating equipment. That is the ratio between the amount of heat delivered during one year ...
0
votes
2answers
134 views

Is making a toilet flush backwards problematic? [closed]

The Coriolis effect impacts the way water tends to circle before going down the drain. Many (most, all?) toilets are designed to work with the Coriolis effect. I am considering a line of toilets ...
0
votes
3answers
92 views

Ventilation setup high sleeper night cooling

I have a high sleeper in my room (width 3,70m, length 4,50m, height 3,30m) consisting of one large plane (yellow) and one window (darker grey). The plance leaves about 80cm space to sleep. The door (...
0
votes
2answers
104 views

What does this equation mean?

$$\propto \dfrac {\text {Cross-Sectional Area}}{\text {Volume}} $$ I've seen this equation on my textbook (physics). Let us imagine that there are two pen with $7$ and $3$ lenght. Which is harder ...
0
votes
4answers
117 views

How are these bricks being supported?

My question is how can all of these bricks be supported by the thin columns on either side? How can there be that much empty space under all of the bricks that the arrow is going through? Looking at ...
0
votes
2answers
248 views

Why are/were sewers made large enough for somebody to walk down in there?

Today, I have been reading a lot about sewer systems on Wikipedia, in the hope that I would find information or at least photos showing what I think of as sewers, namely somewhere under the streets in ...
0
votes
1answer
37 views

Why did they move ancient Egyptian temples to prevent them from water damage instead of encircling them with a dam?

Specifically I'm talking about Abu Simbel temple and Philae temple. Which are close to a reservoir created by Aswan dam. It seems to me easier to build a dam than to move a temple.
0
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1answer
907 views

What is the most efficient way to ionize air?

I have a project to convert wind energy directly to electrical energy with no moving parts. The wind will enter a reducing tunnel for concentration, then go through an unobstructing de-humidifier, ...
0
votes
2answers
72 views

How deep do you have to check for problems underneath a building site?

When you're putting up a new building, you have to check the soil underneath for stability. How deep do you typically have to check? What's the extent of your "due diligence" when ensuring that a ...
0
votes
2answers
703 views

Place a greenhouse: how to orient it for the best effect?

I'm looking for the best orientation (North-East-South-West) of a greenhouse (simplifiable as a rectangular solid). My question is more specifically about the sun position effects (over the times of ...
0
votes
1answer
291 views

How do we define the durability as per density?

We define the durability with the equation as seen below. $$x\propto \frac{\text{Cross-Sectional Area}}{\text{Cross-Sectional Area}\times \text{Length} }$$ Hence $$\therefore x\propto \text{Length}...
0
votes
2answers
72 views

Windproof open doors room design

I live somewhere where it's relatively warm the entire year (around 10ºC is the coldest you'll get in some days during a normal winter). I am dreaming of a house design that I intend to build in the ...
0
votes
1answer
81 views

Could Tesla have REALLY shaken a building with a little oscillator?

I came across this story while reading about Nikola Tesla ground-power scheme. Supposedly, he created a little oscillator that could be plugged into the ground, tuned to the right (resonant) frequency,...
0
votes
1answer
62 views

Do concealed door closers exacerbate wear on a door's hinges?

Not being of an engineering background, I was first inclined to think that a door closer would reduce horizontal load on all hinges and not contribute any support in the vertical dimension. However, ...