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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19 views

How much do I need to trickle my faucet in cold weather (as a function of x,y,z)?

I am told that, in cold weather, I should let my faucet trickle a little to prevent pipes from freezing, especially if some portion of my above-ground pipes are likely to get cold. Are there any rules ...
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1answer
32 views

Is it just surface area alone that causes bridges to freeze?

Scenario: Object 1, a bridge freezes over do to the surface area exposed to the below freezing air. Object 2 has the same surface area exposed to the same air, but its base sits on the ground that is ...
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1answer
68 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,...
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0answers
19 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 &...
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0answers
12 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 ...
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1answer
48 views

calculating energy usage with measuring the temperature

I am an electrical engineer working on a project. My goal of this project is to make an IoT solution where I continuously measure the temperature of room in a building. I want to calculate the amount ...
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1answer
71 views

What does Leonardo da Vinci mean in his statement on arches?

I was recently reading some of Leonardo da Vinci's notes on architecture. One passage on arches states: An Experiment to show that a weight placed on an arch does not discharge itself entirely on ...
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3answers
92 views

can ceramic be used as a building material?

From what I read, concrete has much lower compressive strength than ceramics. So why aren't we using ceramics to build? Is it because ceramic failure is difficult to predict? Because it's hard to ...
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8 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 ...
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2answers
54 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 ...
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0answers
14 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 ...
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2answers
129 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 ...
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2answers
60 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 ...
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1answer
65 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 ...
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3answers
81 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 ...
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1answer
45 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, ...
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2answers
131 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 ...
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2answers
70 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
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1answer
82 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 ...
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1answer
72 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 ...
2
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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-...
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0answers
23 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 ...
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1answer
82 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 ...
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25 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 ...
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2answers
78 views

What are the limits on building very high buildings using certain materials and architectural style?

I played some video games with beautiful environments filled with buildings which can't be found in the real world. And so I'm wondering, would such buildings be even realistically possible to exist ...
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1answer
66 views

How to maintain a static negative pressure in a valve?

My target is to create a valve with multiple inlet capillaries. And my output is a pipe of a larger diameter. I do not want to use any electrical systems, and at the same time, I want to maintain ...
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3answers
86 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 (...
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2answers
75 views

How do I measure max oscillation of building using accelerometer?

For my school project, I am trying to measure the effect of a mass damper by changing the length of the string (that carries the mass), my setup is similar to the following video: https://youtu.be/...
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1answer
303 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 ...
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7answers
433 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?
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3answers
107 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 ...
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2answers
287 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 ...
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1answer
156 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}...
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2answers
92 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 ...
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1answer
43 views

When does window insulation have more impact than attic?

Is there any way to determine either empirically or by convention a rule-of-thumb when one should spend money on insulating windows rather than insulating the attic of a house or building to keep it ...
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2answers
207 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 ...
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1answer
76 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 ...
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1answer
102 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?
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2answers
68 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 ...
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0answers
140 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 ...
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1answer
693 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, ...
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1answer
52 views

Has anyone achieved significant energy savings by increasing the cooling setpoints in retrofit office buildings, in practice?

I have a simulation based research vs. practical experience type question: There are a number of academic research papers available which claim 20% to 40% cooling energy savings by increasing the ...
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1answer
466 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,...
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1answer
182 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 ...
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0answers
35 views

How to estimate the physical parameters of 40% Cu + 60% Mo alloy?

I need to know, or estimate the physical characteristics of the alloy which consists 40% copper and 60% molybdenum. I know only: Density: $9.62 \frac{g}{cm^3}$ Thermal conductivity: $223 \frac{W}{m·K}...
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2answers
1k views

How to make a pulley system with a mechanical advantage of 0.5 [closed]

Problem Hi I was working for an engineering club and we needed to do this as soon as possible: We wanted to make a pulley system with a mechanical advantage of 0.5 I know that we have to do ...
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1answer
112 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 ...
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1answer
115 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 ...
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0answers
474 views

Why can't current tennis sensors measure actual spin in RPM? [closed]

I'm just curious if anyone thinks this can be done. I assume if it was possible somebody would have done it by now. From what I understand, Hawkeye is the only device that can measure RPM. At present, ...
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0answers
91 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 ...