Povzetek Nabavna funkcija v podjetju je eden najpomembnejših segmentov delovanja podjetja. Uspešnost nabavne službe je pogojena s pravilno in z dobro presojo pri izbiri dobavitelja in njegovo končno vlog (vključno pri spremljanju reklamacij). Proces izbire pravega dobavitelja je ena izmed najpomembnejših strateških odločitev vsakega podjetja, saj vpliva na njegovo delovanje, uspešnost in s tem tudi na njegov obstoj. Dobavitelj mora izpolniti pričakovanja kupcev, sicer ne more pričakovati uspeha na trgu. Diplomska naloga se bo osredotočila na težavo rosenja vitrin, ki se je pojavila v eni od trgovin. Po prenovi objekta in zagonu le-tega sta se pojavila na njih led in rosa. S to težavo in tako obsežno smo se srečali prvič. Odprava navedene reklamacije je terjala hitro izvedbo v naj krajšem možnem času s pomočjo predvidevanj in meritev. Dobavitelje se izbira na osnovi več parametrov, kot so kakovost, cena, hitrost dobave in poznavanje kupčevih potreb in želja. Raznolikost kupcev terja večjo prilagodljivost, kar lahko predstavlja večje tveganje pri vpeljavah nestandardnih oziroma ne testiranih rešitev na kupčevo željo. Komunikacija med kupcem in dobaviteljem mora biti usklajena, da se zagotovita najboljša rešitev in izbira produktov. V diplomski nalogi se osredotočam, kako rešiti probleme s pomočjo tehničnih rešitev in kako zadovoljiti kupce s predajo produkta, ki deluje brez napak. Problem smo rešili s pomočjo monitoringa in tudi s predvidevanji, katere ukrepe je potrebno izvesti. Opravili smo več testnih meritev. Rešitev reklamacije je potekala v šestih fazah: • V prvi fazi smo pregledali reklamacijo in jo opisali. V tej fazi smo pregledali vse nastavitve in detajle, kjer bi lahko prišlo do odstopanj. Pregledali smo tesnjenje vitrin na spojih, kako so sestavljene, ali so drsna in ostala vrata pravilno nameščena, ali je zatesnjen dovod pri električnih kablih. • V fazi 2 smo izvedli meritve z naše strani, opredelili težave, jih opisali in poslali poročilo – reklamacijo našemu dobavitelju. • V fazi 3 smo skupaj z dobaviteljem naredili in pripravili načrt kaj je potrebno na objektu preveriti in izmeriti da se reklamacija reši. • V fazi 4 smo opravili skupen prihod na objekt, kjer smo pregledali stanje in opravili prve skupne meritve. določili smo ukrepe za naslednji pregled in meritev. • Faza 5 druga skupna meritev. Pregledali smo stanje, če se je kaj izboljšalo glede na prejšnji obisk in zapisali ugotovitve. • Zadnja faza 6 je bila izvedena s strani zunanjega laboratorija, ki je podal svoje ugotovitve. S pomočjo meritev in testiranj smo prišli do končne ugotovitve, da je največja težava vdor svežega zraka, zaradi katerega se tvori kondenz. V naši reklamaciji si bomo ogledali težavo rosenja vitrin, kjer je sprva kazalo, da je težava na samem izdelku – vitrinah, v končni fazi pa se je na osnovi meritev pokazalo, da je povzročitelj težave neustrezna klimatizacija celotnega objekta in neprimerno prezračevanje. Ključne besede: rosenje, točka rosišča, absolutna vlaga, relativna vlaga Abstract Purchasing function is one of the most important segments in the functioning of company. The success of purchasing department is determined by correct and good judgement when selecting a supplier, and also his final role (including the monitoring of complaints or refunds). The process of selecting the right supplier is one of the most important strategic decisions of every company, since it influences its functioning, success and, consequently, its existence. The supplier has to meet buyers' expectations or else he cannot expect to succeed in the market. This diploma thesis is focused on the problem of steamy display cases, which occurred in one of the shops. After the shop had been renovated and reopened, the steam and ice appeared on display cases. We faced such an extensive problem for the first time. The complaint was dealt with in the shortest time possible, using the predictions and measurements. The suppliers are selected on the basis of several parameters, such as quality, price, speed of supply and understanding costumer's wishes and needs. The variety of different buyers demands more adjustability, which can present a higher risk when introducing nonstandard or untested solutions, which were made on buyer's demand. To ensure the best solution and choice of products, the buyer – supplier communication has to be consistent. This diploma thesis focuses on how to solve the problems using technical solutions and how to satisfy the buyers by delivering flawless products. The problem was solved by monitoring and by predicting which measures should be taken. We performed several test measurements and we also included the external measurement source to achieve more credibility. The complaint was resolved in six phases: • In the first phase, the complaint was examined and described. All settings and details were checked to avoid possible deviations. We checked the sealing of display cases at their joints. We then checked display cases’ construction and whether the slide doors are set properly. We also checked whether the electrical conduit is sealed properly. • In the second phase, we made some measurements and defined the problems. We also described them and sent a report about the complaint to our supplier. • In the third phase, we made a plan with our supplier of what needs to be checked in the building in order to resolve the complaint. • In the fourth phase we examined the building together. We checked the conditions and performed some measurements together. Then we determined the measures that have to be taken for next examination and measurements. • In the fifth phase, we performed another shared measurement. We checked whether the condition had improved since our first visit and we took notes of our findings. • The sixth phase was performed by an outside laboratory, which also presented its findings later With the help of measurements and testing, we concluded that the greatest problem is the invasion of fresh air, which then causes condensation. In our complaint, we will look into the issue of steamy display cases. We first assumed the problem was in the product itself – the display cases. In the final phase and based on the measurements, we ascertained that the problem appeared because of the inappropriate air-conditioning and ventilation of the whole building Keywords: dewpoint, dew point, absolute humidity, relative humidity