Maija Mattinen

Energy Use and Greenhouse Gas Emissions of Air-Source Heat Pump and Innovative Ground-Source Air Heat Pump in a Cold Climate

This article compares climate impacts of two heat‐pump systems for domestic heating, that is, energy consumption for space heating of a residential building. Using a life cycle approach, the study compared the energy use and greenhouse gas (GHG) emissions of direct electric heating, a conventional air‐source heat pump, and a novel ground‐source air heat pump innovated by a citizen user, to assess whether such user innovation holds benefit. The energy use of the heat pumps was modeled at six temperature intervals based on duration curves of outdoor temperature. Additionally, two heat pump end‐of‐life scenarios were analyzed. Probabilistic uncertainty analysis was applied using a Monte Carlo simulation. The results indicated that, in ideal conditions, that is, assuming perfect air mixing, the conventional air‐source heat pumps emissions were over 40% lower and the ground‐air heat pumps emissions over 70% lower than in the case of direct electric heating. Although proper handling of the refrigerant is important, total leakage from the retirement of the heat‐pump appliance would increase GHG emissions by just 10%. According to the sensitivity analysis, the most influential input parameters are the emission factor related to electricity and the amount of electricity used for heating.

Hourly-Based Greenhouse Gas Emissions of Electricity – Possibilities for Households and Companies to Decrease Their Emissions

The various emissions, including GHG emissions, from electricity production are a crucial part of environmental impact assessments of any kinds of products, services and consumption. Usually average annual emissions are used, but electricity market has lately increased interest in daily-based and hourly-based emission coefficients for electricity. In such markets, where technology mixture of the production includes technologies with widely different emission factors, there is potential for large variation in hourly based emission factors and consequently this offers potential for decreasing GHG emissions by efficient real-time based demand management. In this paper, we determine hourly based GHG emission factors and give examples how GHG emissions may be decreased in households and companies by changing the use patterns, and consequently timing of electricity use, the total amount of electricity consumption being unchanged. Electricity production in Finland, as well as the electricity consumption in Finnish households and companies are used as the cases. The examples from households and companies indicate the potential of managing hourly based demand loads and resulting GHG emissions. So far hourly-based emission coefficients have not been used (at least in significant amounts) in demand management in order to reduce emissions and mitigate climate change.

Nearly Zero-Energy Buildings in Finland: Legislation Alternatives for Residential Wood Combustion and the Impact on Population Exposure to Fine Particles

Wood combustion is being promoted as an environmentally friendly energy source in the residential sector, although it’s fine particle emissions and consequential detrimental effects on human health has been clearly shown in recent scientific literature. In Finland, supplementary wood heating is common, and the popularity of masonry heaters in new detached buildings has been on the rise. Finnish legislation concerning EU’s requirements on nearly zero-energy buildings is in preparation, and possibly includes a component that may have an increasing effect on the need of supplementary wood heating. This study demonstrates that the potential increase would cause notable fine particle emissions in the future. We studied several wood consumption scenarios and the resulting PM2.5 concentrations in 2050. In the scenario with the biggest increase in wood consumption, the masonry heaters in new detached buildings would cause an additional 10% rise in the current background concentrations in some suburban areas. Increasing the share of wood heating would also be somewhat counterproductive to the purpose of the Energy Performance of Buildings directive, since the legislation won’t improve the actual energy efficiency of these houses.