The current climate changes require a global response immediately. Every year the use of energy increases, which means that more and more greenhouse gases are released. Which in turn helps accelerate global warming. To reduce the energy use will not be an easy task for mankind. Household and service accounts for about 40% of Sweden’s energy use, and office buildings prove to be among the most energyintensive. Previous research shows that heat-, ventilation- and cooling systems along with lightning are the systems that provide the highest energy consumption and that there is also a great savings potential. In this study, the energy use of a property in a Swedish urban area has been investigated and how the energy is being used by the different systems has been identified. The purpose of this research is to see which measures can give the greatest cost-effective savings. Method used is a case study, which was an energy survey, combined with a literature review of relevant information. Data collection consisted of information from the property owner,inspection of the building and electricity measurements. The result shows that there are great savings to be made. If proposed measures are implemented (see section 4.6), energy consumption for heating can be reduced by 144,9 MWh/year or 32,4%. Energy used by lightning can be reduced by 46,8 MWh/year or 40,3%and other measures can be reduced by 41 MWh/year or 53%. Measures that can be performed for free were considered the most cost-effective, such as lowering the indoor temperature or turning off equipment between days. For measures with investment cost, isolation of the attic was considered most cost -effective with a payoff time of 5 years. To invest in sun cells would reduce the bought electricity with 56,8 MWh/yr. Due to lack of information, assumptions and simplifications were made that could have caused sources of error.

För att tillgodose framtidens växande behov av energi och samtidigt bidra till en långsiktigt hållbar energitillförsel krävs resurs- och energieffektivisering inom flera sektorer. Inte minst inom industrin som år 2016 stod för mer än 50 procent av det globala energibehovet. Tillvaratagandet av befintliga resurser såsom spillvärme från tryckluftsproduktion är en möjlig effektiviseringsåtgärd. Till grund för examensarbetet ligger ett önskemål från koncernen Sandvik AB att utreda besparingspotential och kostnader för reinvestering i en av industrins kompressorcentraler, Götvalsverket. Reinvesteringen avser två nya kompressorer vars spillvärme integreras i industrins befintliga närvärmesystem och möjliggör för minskade resurs- och energikostnader samt utsläpp av CO2. Arbetet syftar till att analysera olika kompressorlösningar utifrån ett ekonomiskt och miljömässig perspektiv. Detta görs med hjälp av insamlad data, känslighetsanalyser och lönsamhetskalkyler med tillhörande LCC. Målet är att kunna besvara olika frågeställningar rörande total investeringskostnad, energi- och resursbesparing samt utsläppsreducering. Två fall av produktion undersöks, dels vid drift enligt Götvalsverkets befintliga produktionstid och dels med en optimerad drifttid för kompressorenheterna. En litteraturstudie har också genomförts där flera studier visar att tryckluft är ett dyrt alternativ för energiproduktion och att implementering av effektiviseringsåtgärder, däribland återvinning av spillvärme, därför kan vara väl grundade investeringar. Även andra fördelar kan kopplas till energieffektivisering, exempelvis förbättrad produktion och arbetsmiljö för anställda. Resultatet av arbetet visade att särskilt ett kompressoralternativ stod ut från de övriga ur både en ekonomisk- och miljömässig synpunkt. Detta alternativ erbjöd inte den billigaste investeringen men däremot var mängden återvunnen värme så pass mycket större än för andra alternativ, att energibesparingen minskade återbetalningstiden drastiskt. Tillvaratagande av befintliga resurser som spillvärme, tillsammans med industrins minskade energianvändning, anses vara en nödvändighet för att kunna säkerställa välmående hos både människor, djur och natur i framtiden. / In order to meet the growing demand for energy in the future, while contributing to a long-term sustainable energy supply, resource and energy efficiency measures are required within several sectors. In 2016 the industry sector accounted for more than 50 percent of the global power demand. The use of existing resources, such as waste heat from compressed air production, is a possible efficiency measure.  Behind this thesis work is a request from the Sandvik AB Group to estimate savings potential and reinvestment costs in one of the industry's compressor centers, Götvalsverket. The reinvestment refers to two new compressors whose waste heat is integrated into the industry's existing district heating system and allows for reduced resource and energy costs as well as a reduction of CO2-emissions.  This work aims to investigate different compressor alternatives from an economic- and environmental perspective. This is done using collected data, a sensitivity analysis and profitability calculations with an attached LCC-analysis. The aim is to answer various questions regarding total investment cost, energy and resource saving as well as emission reduction. Two cases in production are investigated. The first according to the existing operation hours in Götvalsverket and the second case with an optimized operating time for the compressor units.  A literature review has also been conducted where several studies show that compressed air is an expensive alternative to energy production and that implementation of efficiency measures, including waste heat recovery, can be well-founded investments. Other benefits can also be linked to energy efficiency, such as improved production and an improved work environment for employees.  The result of the work showed that one alternative in particular stood out from the other compressor solutions, both from an economic and environmental point of view. This option did not offer the cheapest investment but the amount of recovered waste heat was much larger than for the other alternatives and therefore, energy savings reduced the payback period drastically.  The utilizing of existing resources such as waste heat, together with the industry sector’s reduced energy consumption, is considered a necessity in order to ensure the well-being of people, animals and nature in the future.