This report present the heating and cooling system integration applied in the GLN area, based on a proposed district cooling/heating network design methodology. The cooling load is provided by a mix of direct cooling and refrigeration. To improve the total performance of the district cooling, a method for optimizing the mass flow of lake water has earlier been developed and implemented for one building in the GLN project. This method has in this project been adjusted and developed so that it can now be used for optimizing the lake mass flow for all the connected buildings of the area. The lake water can also be used as a heat source by implementing heat pumps. To study this option, energy integration techniques were applied to access the potential savings in terms of energy bill and CO2 emissions. A comparison between the situation with and without heat pumps was then carried out. The results show that considerable savings can be achieved regarding energy costs and CO2 emissions, respectively 33% and 79%.