The books is good(ish) for it's time, but some of its analysis and forecasts are fundamentally flawed since it falls for the primary energy fallacy by comparing the chemical potential energy (in J) directly to electrical energy (also in J). The two are fundamentally different things and called be compared 1:1. E.g. To heat up your home with natural gas you need ~1J of chemical energy to get 1J of heat into the home, but with a electric heat pump you only need 1/6 J to get 1J of heat.
It is also a product of its time in terms of wind/solar vs nuclear. His forecasts of the impact of solar and wind is based on prices and performance from 2008. Prices have come down an order of magnitude since then, and performance and lifespan have increased drastically.
Heat pumps, and their efficiency (getting more than X Joules of heating for X Joules of electricity) are discussed in chapter 21 Smarter Heating, see for example the diagram and discussion on page 150: <a href="https://www.withouthotair.com/c21/page_150.shtml" rel="nofollow">https://www.withouthotair.com/c21/page_150.shtml
I imagine the economics (and perhaps technical improvements) of some things may have changed more than the book could forecast. But heat pumps were definitely understood by the author.
Yes, I disagree with some of his takes but he was spot on regarding heat pumps:
> Let me spell this out. Heat pumps are superior in efficiency to condens-
ing boilers, even if the heat pumps are powered by electricity from a
power station burning natural gas. If you want to heat lots of buildings
using natural gas, you could install condensing boilers, which are “90% ef-
ficient,” or you could send the same gas to a new gas power station making
electricity and install electricity-powered heat pumps in all the buildings;
the second solution’s efficiency would be somewhere between 140% and
185%. It’s not necessary to dig big holes in the garden and install underfloor
heating to get the benefits of heat pumps; the best air-source heat
pumps (which require just a small external box, like an air-conditioner’s)
can deliver hot water to normal radiators with a coefficient of performance
above 3.
I want to remind that natural gas fired heat pumps operating with central European winter temperatures on the cold side and toasty warm indoors living room "by the fire place/any clothes are too warm just sitting not even exercising at all" are well established technology.
They're just usually deployed for frozen warehouses, factories that actively freeze large amounts of (usually food), and AFAIK the occasional ice(hockey) rink.
Shitty types that don't even bother with any decent controls/pumps (those 90% boilers use a water loop circulation pump and a combustion air blower together with a bunch of sensors and valves) run propane-fired in many camper vans to do the fridge.
But at the scale of an apartment building fit for 50+ residents, a natural gas fired central heat pump can be _quite_ efficient and economical.
Thermodynamically they're a heat engine with high combustion/flame temperature that uses the warm side as the heat sink, mated to a heat pump that consumes the produced "mechanical/electrical grade" power to pump heat from the cold side to _also_ the warm side.
You save the turbine! Also the electrics but they're probably not even that expensive relative to the rest of the 200MW-class combined cycle natural gas power plant.
_aavaa_ · · focus · HN ↗
It is also a product of its time in terms of wind/solar vs nuclear. His forecasts of the impact of solar and wind is based on prices and performance from 2008. Prices have come down an order of magnitude since then, and performance and lifespan have increased drastically.
azornathogron · · focus · HN ↗
I imagine the economics (and perhaps technical improvements) of some things may have changed more than the book could forecast. But heat pumps were definitely understood by the author.
ZeroGravitas · · focus · HN ↗
> Let me spell this out. Heat pumps are superior in efficiency to condens- ing boilers, even if the heat pumps are powered by electricity from a power station burning natural gas. If you want to heat lots of buildings using natural gas, you could install condensing boilers, which are “90% ef- ficient,” or you could send the same gas to a new gas power station making electricity and install electricity-powered heat pumps in all the buildings; the second solution’s efficiency would be somewhere between 140% and 185%. It’s not necessary to dig big holes in the garden and install underfloor heating to get the benefits of heat pumps; the best air-source heat pumps (which require just a small external box, like an air-conditioner’s) can deliver hot water to normal radiators with a coefficient of performance above 3.
namibj · · focus · HN ↗
They're just usually deployed for frozen warehouses, factories that actively freeze large amounts of (usually food), and AFAIK the occasional ice(hockey) rink.
Shitty types that don't even bother with any decent controls/pumps (those 90% boilers use a water loop circulation pump and a combustion air blower together with a bunch of sensors and valves) run propane-fired in many camper vans to do the fridge. But at the scale of an apartment building fit for 50+ residents, a natural gas fired central heat pump can be _quite_ efficient and economical.
Thermodynamically they're a heat engine with high combustion/flame temperature that uses the warm side as the heat sink, mated to a heat pump that consumes the produced "mechanical/electrical grade" power to pump heat from the cold side to _also_ the warm side. You save the turbine! Also the electrics but they're probably not even that expensive relative to the rest of the 200MW-class combined cycle natural gas power plant.