Debug: Database connection successful Dome heating requirements / Exploration to Settlement Creation / New Mars Forums

New Mars Forums

Official discussion forum of The Mars Society and MarsNews.com

You are not logged in.

Announcement

Announcement: This forum is accepting new registrations via email. Please see Recruiting Topic for additional information. Write newmarsmember[at_symbol]gmail.com.

#1 Yesterday 07:15:57

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 30,051

Dome heating requirements

We will be on a very cold place when we live inside the 200m diameter by approximate 120m tall parabolic dome that we will build a small settlement within capable of provide for a permanent stay on mars once fully outfitted. The piled regolith gives 2 things with the activity in radiation protection but also insulation from the cold mars.

We have humidity, scrubbing of internal air, waste management, water creation, fuel and air to breath and so many more things.

AI generated content for the questions

Calculating the exact heating wattage for a dome on Mars requires detailed engineering specifications for the dome's construction materials and internal environment, but a rough estimate based on available data suggests the heating load would be tens to hundreds of megawatts (MW), primarily due to extreme heat loss. 

The key factors that make heating a challenge on Mars are: Extreme temperature difference: The average temperature on Mars is around -63°C (-82°F), with nighttime temperatures plummeting to -73°C (-100°F) or lower. Maintaining a comfortable internal temperature (e.g., 20°C or 68°F) would require a temperature differential of over 80-90°C, leading to significant heat flow out of the dome.

Minimal atmospheric insulation: The Martian atmosphere is extremely thin, about 0.6% of Earth's atmospheric pressure, and composed mostly of carbon dioxide. This provides virtually no insulating "thermal blanket," allowing heat to dissipate rapidly into space.

High heat loss: The thin atmosphere combined with the low thermal conductivity of Martian soil (which acts as a good insulator for buried sections, but means heat loss to the air is a major concern for exposed surfaces) means that any exposed surface will lose heat very quickly through a combination of convection (minimal but present) and significant radiative transfer. 

Estimated Heat Loss Calculation (Conceptual) Engineers on forums and in research have made preliminary calculations based on typical construction methods and Martian conditions: One such estimate for a 150m diameter, 75m tall dome (a similar scale to yours) with a 6cm thick glass shield (an R-value of ~0.06 m²K/W) suggests a heat flux of around 2,667 W/m² during a winter night.For your 200m diameter dome, the exposed surface area would be significant (the surface area of a 200m diameter hemisphere is \(\approx 62,800\,\text{m}^{2}\)).Multiplying the area by the heat flux gives a massive heat loss in the range of 100 MW or more. 

This energy demand is enormous and highlights the need for: Exceptional insulation materials (far better than a single layer of glass).Potentially burying large portions of the habitat to use the regolith as insulation.Integration of life support systems, computing, and other activities as internal heat sources to recover as much thermal energy as possible.Robust, high-efficiency power sources on Mars to meet this demand

The wattage required to heat a Mars dome depends heavily on internal temperature requirements, the specific thermal properties of the regolith, and the Mars environment. Using standard engineering formulas and typical Mars regolith properties, the estimated heating wattage for a 200m diameter, 120m tall dome with a 10m regolith barrier is likely to be in the range of several hundred kilowatts (kW) to over a megawatt (MW) to counteract heat loss. 

This calculation involves several key factors: 
Heat Loss Formula: The basic principle for conductive heat loss is given by Fourier's law: \(Q=(\frac{k}{t})*A*(T_{inside}-T_{outside})\).\(Q\) is the rate of heat transfer (Watts).\(k\) is the thermal conductivity of the material.\(t\) is the thickness of the insulation.\(A\) is the surface area.\(T_{inside}\) and \(T_{outside}\) are the internal and external temperatures.

Key Parameters:Dome Surface Area: A dome of this size has a significant surface area exposed to the Martian environment.Thermal Conductivity (\(k\)): Martian regolith is a poor thermal conductor, with an average conductivity around 0.039 W m⁻¹ K⁻¹ in the shallow subsurface. This low conductivity is a major advantage for insulation.

Temperature Difference: Mars' surface temperatures vary widely, from around -153°C to 20°C (-225°F to 70°F). The required internal temperature for human habitation would likely be around 20°C (68°F). The external temperature would vary seasonally and daily, requiring the heating system to handle a large temperature differential, especially during Martian night and winter.

Other Factors: The presence of a CO₂ atmosphere (which increases conductivity slightly compared to a vacuum), internal air pressure, and potential ground ice or salt cementation can affect the effective thermal properties.

Estimated Wattage:
One conceptual design for a 250m diameter Mars habitat (Craterhab) lists a power input of 116 kW, though the exact shielding and internal conditions are not specified. The 10m thick regolith provides excellent insulation, but the sheer surface area of a 200m dome results in a substantial total heat loss that needs constant heating to counteract.A full engineering calculation with specific \(T_{inside}\) and minimum \(T_{outside}\) values is needed for a precise figure. The required wattage would represent a major power demand for the habitat


response after adding in waste heat from a 40 kilowatt reactor

The 40-kilowatt (kW) reactor produces a total thermal output (waste heat plus useful power) that can be harnessed. A 40 kWe (kilowatt-electric) reactor designed for Mars surface power would actually produce around 250 kW of thermal energy as waste heat, which is more than sufficient to heat the massive regolith barrier. The amount of wattage required for the regolith barrier depends entirely on the desired internal temperature of the habitat and the external Martian environmental conditions, but the available waste heat from the reactor is a substantial 250 kW. 

Available Waste Heat A nuclear reactor generating 40 kWe (kilowatts of electricity) has a thermal efficiency of roughly 15-20%. Therefore, the total heat produced (\(Q_{total}\)) is significantly higher than the electrical output.

The waste heat (\(Q_{waste}\)) can be estimated as the difference between total thermal power and electrical power: Total Thermal Power: Approximately 250 kWth (kilowatts thermal).

Electrical Output: 40 kWe.Waste Heat Available: \(\approx \) 210 kW (250 kW - 40 kW). This 210 kW of heat can be passively transferred via heat pipes to the surrounding regolith. Heating Requirements & Thermal Properties The need for heating is to counteract heat loss to the extremely cold Martian environment. 

Average Martian Temperature: The average surface temperature is around -63°C (210 K) but can plummet to -140°C at the poles.

Regolith Thermal Conductivity:
Martian regolith is a poor thermal conductor, with an average conductivity of approximately 0.039 W/(m·K). This low conductivity provides natural insulation. Given the immense size of the structure (200m diameter, 120m tall dome with a 10m thick barrier), the massive volume of regolith will have significant thermal mass and excellent insulating properties. The low thermal conductivity means that heat loss to the outside environment would be slow. 

Conclusion 
The 210 kW of available waste heat from the 40 kWe nuclear reactor is ample to warm the regolith radiation barrier and likely the habitat itself, potentially even requiring a dedicated heat rejection system (radiator panels) to prevent overheating if not all the waste heat is needed for the habitat's thermal management. The primary engineering challenge would be efficiently distributing the heat throughout the large volume of the regolith barrier as needed for thermal control

I am sure Caliban can confirm this to be close to what we need and could do.

The greenhouse will add to this baseline requirement.

Massive Mars Greenhouse Effect Domes Would Heat Themselves

Talks to surface glass greenhouse structures and not really the dome we are planning.

Offline

Like button can go here

#2 Yesterday 07:34:17

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 23,650

Re: Dome heating requirements

This post is reserved for an index to posts that may be contributed by NewMars members.

This new topic is a welcome addition to the body of knowledge that will be needed to guide development of a dome habitat on Mars.

Index:

(the)

Offline

Like button can go here

Board footer

Powered by FluxBB