Saturday Feb 04, 2023

Solar-powered Heat Pumps Warm Upper Peninsula Homes for Less – Michigan Technological University


Two new Michigan Tech studies show how heating with electric heat pumps is good for
the environment — and the Upper Peninsula’s wallet, especially when paired with solar

Long, cold, snowy winters are familiar to Nelson Sommerfeldt, who grew up on the Keweenaw Peninsula, graduated from Michigan Technological University
in 2004, and for the past 10 years has been researching sustainable energy at the
Royal Institute of Technology in Stockholm, Sweden. Nordic winters haven’t been any
warmer or shorter, but there is a major difference: In Sweden, electric heat pumps
are the most common form of household heating.

Propane heating is common throughout Michigan’s Upper Peninsula (U.P.), and it’s expensive.
Knowing this, Sommerfeldt came back to Tech as a visiting scholar, teaming up with
Tech’s solar photovoltaic (PV) experts to find out if solar heat pumps are a viable
heating method for the region.

A heat pump is an air conditioner running in reverse. Working at temperatures as low
as minus 5 degrees Fahrenheit, the pump takes cold air from outside and produces warm
air inside. It runs on electricity but is three times more efficient than the space
heater under your desk. That efficiency is vital for dealing with the U.P.’s high
electricity prices — but the real savings come from using solar PV. MTU studies have
previously shown that
solar PV is cheaper than grid electricity. The latest studies explore whether enough solar energy can be generated and used by the heat pump to keep an average U.P. home warm — and
what it will cost.

Diagram of a building energy system with PV generation (Epv), appliance loads (Eapp), heat pump loads (Ehp) and a grid connection (Egrid). Image credit: Pearce, Sommerfeldt via Appropedia

A Propane Alternative

In the first study, the team looked at rural, residential buildings in the U.P. that
rely on propane. They tested multiple heating system designs, with and without solar,
all connected to the grid. Without any subsidies, they found that
heat pumps have lower lifetime cost and greenhouse gas (GHG) emissions. When solar PV is added to the system, GHG emissions are reduced by 50% immediately,
and because the heat pump is supported by grid electricity, the savings are expected
to increase over time.

“Most Yoopers would save money by upgrading their propane heaters with heat pumps
and solar. Upper Peninsula Power Company’s high prices can be a barrier, but UPPCO’s
new electric heating rates combined with existing solar PV rebates should tip the
scales in favor of solar heat pumps.”Nelson Sommerfeldt, Sustainable Energy Researcher

 Explore Other Aspects of Sommerfeldt’s Research

Cheaper Than Natural Gas

While propane has been headlining the news lately, most U.P. residents use natural
gas for heating. In the second study, the team tested
how net-zero energy homes using solar heat pumps compare economically to homes using
natural gas
. The study, conducted in the neighboring towns of Sault Ste. Marie in the U.S. and
Canada, used current electricity and gas rates combined with …….


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